Cathepsin B-responsive and gadolinium-labeled branched glycopolymer-PTX conjugate-derived nanotheranostics for cancer treatment

Multi-modal therapeutics are emerging for simultaneous diagnosis and treatment of cancer. Polymeric carriers are often employed for loading multiple drugs due to their versatility and controlled release of these drugs in response to a tumor specific microenvironment. A theranostic nanomedicine was designed and prepared by complexing a small gadolinium chelate, conjugating a chemotherapeutic drug PTX through a cathepsin B-responsive linker and covalently bonding a fluorescent probe pheophorbide a (Ppa) with a branched glycopolymer. The branched prodrug-based nanosystem was degradable in the tumor microenvironment with overexpressed cathepsin B, and PTX was simultaneously released to exert its therapeutic effect. The theranostic nanomedicine, branched glycopolymer-PTX-DOTA-Gd, had an extended circulation time, enhanced accumulation in tumors, and excellent biocompatibility with significantly reduced gadolinium ion (Gd

Castor Bean Cake Protein-based Biodegradable Films: Gallic Acid Effect

Abstract: The objective of this work was to evaluate the effect of gallic acid (GA) concentration on some physical properties and biodegradability of films produced with proteins extracted from the castor bean cake. The films, prepared by the casting technique, showed homogeneous and brownish appearance. As the GA concentration increased (from 0 to 10 g/100 g protein), the films gradually became darker and more opaque; while the gloss had few significant differences. Solubility, tensile strength and elasticity modulus values of films varied due to changing concentrations of gallic acid. Elongation at break and water vapor permeability values did not have significant changes. A 60% mineralization value of the film containing GA was obtained at 21 days, evidencing its biodegradability. These dark and opaque films could be used in agriculture, specifically in seedling bags as the dark color decrease the incidence of light, preventing root weakening, and the seedlings can be transplanted directly without removal of the film.

Tratamento de lixiviado por processos combinados: coagulação/floculação, air stripping, ozonização e lodo ativado / Leachate treatment by combined processes: coagulation/flocculation, air stripping, ozonation and activated sludge

RESUMO Os lixiviados de áreas de disposição de resíduos municipais apresentam, em geral, alta complexidade, variabilidade, toxicidade, recalcitrância e alta concentração de nitrogênio amoniacal. Neste estudo, aplicaram-se técnicas combinadas para o tratamento de um lixiviado, a saber: coagulação/floculação (C/F), air stripping e ozonização, combinados com o tratamento por lodo ativado com/sem inserção de carvão ativado. O processo de C/F levou a uma redução na demanda química de oxigênio (DQO) de 58,1% e na cor, de 85,6%. O air stripping foi realizado em pH>12 e obteve-se diminuição dos níveis de nitrogênio amoniacal para abaixo de 60 mg.L-1. O processo de ozonização, com consumo de ozônio de 397 mgO3.L-1 e 2.376 mgO3.L-1, apresentou bons resultados, com aumento de 59,4% na relação DBO5/DQO e uma redução de toxicidade superior a 85%. Obteve-se melhor eficiência para o lodo ativado sem carvão ativado, com lixiviado pré-tratado por C/F + air stripping + ozonização (400 mgO3.L-1). Tal combinação resultou em uma redução de 90,6% na DQO do lixiviado e mais de 99% nos níveis de nitrogênio amoniacal.

ABSTRACT Leachate from waste disposal areas generally presents high complexity, variability, toxicity, recalcitrance and high concentration of ammonia nitrogen. In this work, combined techniques for the treatment of leachate were applied, namely: coagulation/flocculation, air stripping and ozonation combined with activated sludge treatment with/without activated carbon. The coagulation/flocculation process led to a COD reduction of 58.1% and color removal of 85.6%. The air stripping was performed at pH>12 and reduced ammonia levels below of 60 mg.L-1. The ozonation process (ozone consumption of 397 mgO3.L-1 and 2376 mgO3.L-1) presented good results. It was observed a BOD5/COD increase of 59.4% and a toxicity reduction of more than 85%. The best efficiency was observed with sludge activated without activated carbon for the pre-treated leachate by coagulation/flocculation + air stripping + ozonation (400 mgO3.L-1). This combination resulted in a COD reduction of 90.6% and more than 99% of ammonia nitrogen removal.

Assessment of petroleum biodegradation for Bacillus toyonensis by the using redox indicator 2,6 dichlorophenol indophenol / Avaliação da biodegradação do petróleo por Bacillus toyonensis, usando o indicador redox 2,6 diclorofenol indofenol

Petroleum degrading microorganisms have been isolated from different environments with the purpose of being used in bioremediation processes in areas impacted by petroleum spills. The objective of this study was to evaluate the ability of Bacillus toyonensis AM07 strain to metabolize petroleum compounds. The strain was isolated from the effluent dike of the Urucu Petroleum Province, Coari - Amazonas, Brazil. The degrading activity of B. toyonensis was evaluated by the colorimetric method using the redox indicator 2,6-dichlorophenol indophenol (DCPIP). Thus, the microorganism was inoculated into minimal medium with DCPIP, and with petroleum as the sole carbon source. The degradation potential of the microorganism was found by changing the DCPIP staining and absorbance readings 600nm. The results obtained demonstrated that the bacterial strain was able to degrade petroleum by altering the color of the medium from blue to colorless and by reducing the concentration of the indicator in the absorbance readings. B. toyonensis AM07 strain has shown good performance in the petroleum degradation assays and may be used in the future in remediation technologies for hydrocarbon impacted environments.

Microrganismos degradadores de petróleo têm sido isolados de diferentes ambientes com a finalidade de serem utilizados em processos de biorremediação de áreas impactadas com derrames de petróleo. O objetivo deste estudo foi avaliar a capacidade da linhagem de Bacillus toyonensis AM07, isolada do dique de efluente da Província Petrolífera de Urucu, Coari - Amazonas, Brasil, em metabolizar compostos do petróleo. A atividade degradadora do B. toyonensis foi avaliada pelo método colorimétrico, utilizando indicador redox 2,6-diclorofenol indofenol (DCPIP). Assim, o microrganismo foi inoculado em meio mínimo com DCPIP e petróleo como única fonte de carbono. O potencial de degradação do microrganismo foi constatado mediante a mudança de coloração DCPIP e leituras de absorbância 600nm. Os resultados obtidos demonstraram que a cepa bacteriana foi capaz de degradar petróleo, alterando a coloração do meio de azul para incolor e reduzindo a concentração do indicador nas leituras de absorbâncias. A cepa de B. toyonensis AM07 mostrou bom desempenho nos ensaios de degradação do petróleo, podendo ser utilizada, no futuro, em tecnologias de remediação de ambientes impactados por hidrocarbonetos.

Application value of manganese-loaded caramelized carbonaceous nanospheres for synchronized breast cancer MRI and photothermal therapy / 中华放射学杂志

Objective To investigate the application value of pH sensitive manganese-loaded caramelized carbonaceous nanospheres (Mn-CNS) in the synchronous MRI and photothermal therapy for breast cancer. Methods Anhydrous glucose was used as carbon source to prepare caramelized carbonaceous nanospheres(CNS).Mn2 +was absorbed and bonded to its surface to obtain the Mn-CNS.The MR signal values of aqueous solutions of Mn-CNS under different pH(pH=7.4,6.0,5.0)with different Mn2+concentrations(0,0.14,0.28,0.57,1.14 and 2.28 mmol/L)were measured to obtain the relaxation rate.The cell counting kit-8(CCK-8)assay was used to determine the effect of Mn-CNS on the viability of 4T1 cells. Pathological examination was used to evaluate the systemic toxicity. Inductively coupled plasma mass spectrometry (ICP-MS) was used to analyze Mn uptake by different cell lines (human breast cancer cells MCF-7, human normal mammary epithelial cells MCF-10A and human macrophages cells). The 4T1 tumor-bearing BALB/c mice were divided randomly into four groups (6 mice per group): (1) normal saline (intratumoral injection)plus near infrared laser(NIR);(2)normal saline(intravenous injection)plus NIR;(3) Mn-CNS(intratumoral injection)plus NIR;(4)Mn-CNS(intravenous injection)plus NIR.After intratumoral injection for 30 min and intravenous injection for 12 h,the tumors were continuously irradiated with 808 nm laser for 10 min,the temperature changes and relative tumor volume were recorded.The MRI was obtained at different time point(pre-injection and post-injection at 15 min,30 min,1 h,4 h,8 h,12 h,24 h,48 h,4 d, respectively)with the dose of Mn-CNS(4 mg Mn/kg)by intravenous injection.The changes of Mn2+content before and after Mn-CNS incubation and the tumor volume differences among each group were compared by t test.Results The values of r1were 0.18 L·mmol-1·s-1(pH 5.0),3.48 L·mmol-1·s-1(pH 6.0)and 5.42 L· mmol- 1·s- 1(pH 7.4), respectively. The cells viability of 4T1 were all above 90 % when the cells were incubated with Mn-CNS at different concentrations (25, 50, 100 and 200 μg/ml). MCF-7 and human macrophages cells were ingested Mn2+.The Mn2+amount before and after uptake were significant difference(P<0.05).The MCF-10A had a slight uptake of Mn2+which was not statistically significant(P>0.05).After 10 minutes of the laser exposure (2 w/cm2), the change of temperature with tumor among different groups were shown as follow:Mn-CNS(intratumoral injection)>Mn-CNS(intravenous injection)>normal saline(intravenous injection)>normal saline (intratumoral injection). After photothermal therapy, the relative tumor volumes of Mn-CNS (intratumoral injection)and normal saline(intratumoral injection)were statistically different(t=-2.724,P<0.05). Meanwhile,the relative tumor volumes also showsd significant difference among Mn-CNS(intravenous injection) and normal saline (inject intravenous injection) groups (t=-5.193,P<0.05). After intravenous injection of Mn-CNS in 4T1 tumor-bearing mice, the signal intensity of T1gradually increased and reached the peak of enhancement at 4 h after which the signal intensity remained stable and decreased slightly at 12 h,then gradually decreased to normal. The T1signal intensity of kidney was consistent with that of the tumor and higher. Meanwhile, the degree of liver tissue enhancement was the lowest. Conclusions Mn-CNS is highly biocompatible and self-degradable,it can targeted MRI and achieve precise photothermal therapy simultaneously, which is of great value in the integrated diagnosis and treatment of breast cancer.

Advance in research of biodegradable mesoporous silica nanoparticles / 药学学报

Mesoporous silica nanoparticles (MSNs) have been widely used as drug carriers in the diagnosis and treatment of diseases due to their specific characteristics, which include a large surface area, ordered mesoporous structures, easy surface modification and feasible sustained release action for encapsulated drugs. With the research development of MSNs, the biodegradability and removability of mesoporous silica nanomaterials have attracted considerable attention in the clinical application of the MSNs-based formulations. This paper was prepared to emphasize the preparation approaches of biodegradable mesoporous silica nanoparticles through the metal oxide doping method and the organic compound doping method. We discussed the biodegradable mechanism and process of such nanoparticles, and finally, provided an insightful and helpful review of the prospective application of the biodegradable mesoporous silica nanoparticles in medical field.

Application perspectives of polyhydroxyalkanoates / 生物工程学报

Polyhydroxyalkanoates are polyesters of hydroxyalkanoates synthesized by many bacteria and haloarchaea as carbon and energy storage materials. There are more than 150 types of polyhydroxyalkanoate monomers reported, resulting in a variety of Polyhydroxyalkanoates with diverse properties. The material variability, nonlinear optical properties, piezoelectric properties, gas barrier properties, thermoplasticity, biodegradability, and biocompatibility allow polyhydroxyalkanoates to be used for plastic packaging, chiral chemicals generation, medicine, agriculture and bio-energy fields. This review introduces the current applications and future development of polyhydroxyalkanoates.

A novel lacrimal duct prosthesis and its biodegradation and biocompatibility / 中华实验眼科杂志

Background The primary management for nasolacrimal duct obstruction is the combination of lacrimal duct probing with lacrimal duct stent implantation.However,conventional implant is undegradable.New degradable lacrimal duct prosthesis based on biopolymer materials is a research hotspot.Objective This study described herein a preparation method of novel degradable lacrimal duct prosthesis and its application.Methods A new degradable lacrimal tube stent was prepared with compound of poly L lactic acid (PLLA) and polycaprolactone (PCL) (6:4) and 15％ polyethylene glycol (PEG).Thirty-two Japanese rabbits aged 3-4 months were randomized into postoperative 1-week group,postoperative 4-week group,postoperative 8-week group and postoperative 16-week group.The degradable lacrimal tube stents were inserted into the lacrimal ducts of the left eyes of the rabbits.The prosthesis was removed in corresponding time points according to grouping,and the integrity and weight of the prosthesis were evaluated.The mucosal findings of the operative eyes were examined under the endoscope,and the histopathological and inflammatory reaction was observed by hematoxylin & eosin stain.The ultrastructure of the lacrimal mucosal surface was examined under the scanning electron microscope.The use and care of the rabbits complied with the Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission.Results The new degradable PLLA:PCL+15％ PEG lacrimal duct stents were smooth,flexible and hydrophilic tubes.The removed tubes were intact in the postoperative 1-week group,however,the rupture of the tubes appeared in the postoperative 4-week group,while discrete pieces of the tubes were seen in the postoperative 16-week group.The weight-loss rates of the tubes were (13.44±6.59)％,(23.96±6.33)％,(55.08-± 6.55) ％ and (78.00±8.74) ％ in the postoperative 1-week group,postoperative 4-week group,postoperative 8-week group and postoperative 16-week group,respectively,and the weight-loss rate of the tubes was significantly higher in the postoperative 16-week group than those in the postoperative 8-week group (q =4.27,P＜0.05).No significant difference was found in the weight-loss rate of the tubes between postoperative 1-week group and postoperative 4-week group (q =1.71,P＞0.05).The edema,hyperemia and mild proliferation of the lacrimal mucosal were exhibited in the eyes of the postoperative 4-and 8-week groups,and the mucosal findings were almost normal in the eyes of the postoperative 16-week group under the endoscope.Histopathological examination showed a large number of inflammatory cells in the postoperative 1-,4-and 8-week groups.However,few inflammatory cells were seen in the postoperative 16-week group.Mucosal folds,microvillus decrease and disorder were displayed in the lacrimal duct of the postoperative 8-week group,and no evident abnormality was seen in the lacrimal duct mucosal surface.No postoperative complication occurred in all the rabbits.Conclusions PLLA:PCL+15％ PEG lacrimal duct stent has an appropriate degradation speed and good biocompatibility after implant in rabbits,and its decay period of mechanical strength could match lacrimal duct healing period.

Preparation and Properties of Rifampicin-loaded Pluronic L61-PBSu Nanoparticles / 中国药学杂志

OBJECTIVE: To study the preparation of pluronic-modified biodegradable poly(butylene succinate) (PBSu) nanoparticles (NPs) and evaluate the release kinetics of the drug-loaded PBSu NPs and the cytotoxicity of the NPs, so as to provide a new platform for the application of biodegradable PBSu in drug delivery. METHODS: Pluronic L61-modified PBSu NPs were prepared by emulsification method, and the morphology of the NPs was observed by transmission electron microscopy. The in vitro release kinetics of the rifampicin-loaded L61-PBSu NPs at 37 ℃ was studied. The cytotoxicity of the L61-PBSu NPs against human ovarian cancer cells (OVCAR-3) was evaluated by MTT assay. RESULTS: The drug-loaded NPs had a unimodal distribution with an average size of (140±7) nm. The drug encapsulation efficiency attained 64.98%. The release time reached 27 h when the cumulative release percentage was 90%. The release kinetics followed non-Fickian mechanism. The NPs demonstrated very low cytotoxicity against OVCAR-3 cancer cells. Modification by L61 improved biocompatibility. CONCLUSION: The Pluronic-modified PBSu NPs are easy to prepare, biocompatible, and show great promise as a new passive targeting platform for controlled release of insoluble drugs.

Processing, properties and application of poly lactic acid (PLA) fiber / 生物工程学报

Poly lactic acid (PLA) fibers a biodegradable fiber produced from PLA resin by melt spinning, solvent spinning or electrostatic spinning. Based on the excellent safety, comfortability, environmental protection and good mechanical properties, PLA can be widely applied in textile fabric, nonwoven, filler fabric and many downstream health products application, such as sanitary napkins, baby diapers, facial masks, and wipes.

The application of drug-eluting biodegradable magnesium alloy stent in treating esophageal benign stricture:current research status and prospect / 介入放射学杂志

Stent implantation plays a more and more important role in the treatment of benign esophageal stenosis. Metal stents are most commonly used in the clinical practice, which can be classified into permanent stents and temporary retrieval stents. Permanent implantation of metal stents is easy to cause complications such as inflammatory hyperplasia, in-stent restenosis, perforation, bleeding, etc. Temporary retrieval stents should be removed with one week after it is implanted in order to avoid esophageal scar tissue repair and in-stent tissue hyperplasia, which can cause difficulty in its removing and produce higher recurrence rate of esophageal restenosis. Clinically, drug-eluting stents have already been used in cardiovascular system procedures, but at present the gastrointestinal drug-eluting stents are still in development and animal experiment stage. Biodegradable magnesium alloy stents have been widely employed in cardiovascular system procedures. With the rapid development of biological engineering materials, drug-eluting magnesium alloy stent has become a hot spot and the frontier in research field. This paper aims to make a comprehensive review about the current research status and prospect of the drug-eluting magnesium alloy stents, focusing on the stent technology, stent molding, coating modification, and the treatment of drug-eluting.

Study on injectable paclitaxel loaded PCL/PEG/PCL thermosensitive hydrogels / 国际生物医学工程杂志

Objective To construct an injectable controlled delivery system of paclitaxel based on thermosensitive PCL1250-PEG1500-PCL1250 hydrogels. Methods A thermosensitive PCL1250-PEG1500-PCL1250 triblock copolymer was synthesized by ring-opening polymerization of e-CL using PEG (Mw=l 500) as the initiator and Sn(Oct)2 as the catalyst. The synthesized PCL1250-PEG1500-PCL1250 copolymers were characterized for their composition,structure, and molecular weight via 1H NMR and GPC techniques. A series of Paclitaxel loaded hydrogels with various predesigned hydrogel concentrations and initial drug loadings were prepared to investigate their gelation ability, in vitro drug release behavior and in vivo biodegradability. Results The results calculated from 1H NMR and GPC indicated that EG/CL ratio(1.55) was consistent with the initial feed ratio(1.6), which offered a strong proof to their composition and molecular structure. The thermosensitive PCL1250-PEG1500-PCL1250 hydrogels exhibited a desirable sol-gel transition ability within the concentration range of 15%-30%. The in vitro release rate of paclitaxel from the paclitaxel/PCL1250-PEG1500-PCL1250 hydrogels was controllable by altering the hydrogel concentrations and initial drug loadings. The PCL1250-PEG1500-PCL1250 hydrogels showed a good in situ gelation ability after subcutaneously injected into mouse back. The in situ formed hydrogels gradually degradated with time and almost disappeared after 45 days in vivo. Conclusion Both the controllable drug release behavior and promising biodegradability of this new thermosensitive PCL1250-PEG1500-PCL1250 hydrogels paved a way to develop a novel delivery system for paclitaxel.

Caracterização e tratabilidade biológica dos efluentes líquidos gerados em cabines de pintura de uma indústria moveleira / Characterization and treatability of wastewater from a dying hood of a furniture industry

O objetivo deste trabalho foi caracterizar os efluentes gerados em cabines de pintura de uma indústria moveleira e avaliar a eficiência de sistemas biológicos (anaeróbio e aeróbio) para o seu tratamento. O efluente industrial apresentou elevado teor de matéria orgânica (DQO total de 634 a 2.790 mg.L-1; DBO5 total de 360 a 972 mg.L-1) e baixos teores de macronutrientes (NTK de 1,9 mg.L-1 e Ptotal de 0,5 mg.L-) e metais tóxicos. Os ensaios de tratabilidade em reator UASB (~25ºC e tempo de detenção hidráulica - TDH = 10 horas), indicaram uma eficiência máxima de remoção de matéria orgânica de 90 por cento na composição volumétrica 70:30 (efluente industrial:esgoto sanitário). A alimentação do reator UASB só com efluente industrial resultou em acúmulo de ácidos graxos voláteis e inibição microbiana, mas o uso de pós-tratamento aeróbio (TDH = 96h) garantiu elevada eficiência global (~88 por cento) de remoção de matéria orgânica.

The main objective of this work was to characterize the wastewater from the dying hood of a woven furniture industry, and to assess the efficiency of biological processes (anaerobic and aerobic) for its treatment. The physical-chemical characterization of the industrial wastewater showed a high organic matter content (total COD from 634 to 2,790 mg.L-1; total BOD5 from 360 to 972 mg.L-1), low content of macronutrients (NTK of 1.9 mg.L-1 and P of 0.5 mg.L-1) and toxic metals. The anaerobic degradation tests in a bench-scale UASB reactor (25ºC and hydraulic retention time - HRT = 10 hours) showed that a maximum removal efficiency of 90 percent was obtained when the reactor was fed with 30 percent raw sewage and 70 percent industrial wastewater. The feeding of UASB reactor with only industrial wastewater resulted in volatile fatty acids accumulation and microbial inhibition; however, the use of aerobic post-treatment (HRT = 96 hours) granted a high (~88 percent) organic matter removal efficiency.

Anaerobic biodegradability of dairy wastewater pretreated with porcine pancreas pipase

Lipids-rich wastewater was partial hydrolyzed with porcine pancreas lipase and the efficiency of the enzymatic pretreatment was verified by the comparative biodegradability tests (crude and treated wastewater). Alternatively, simultaneous run was carried out in which hydrolysis and digestion was performed in the same reactor. Wastewater from dairy industries and low cost lipase preparation at two concentrations (0.05 and 0.5 percent w.v-1) were used. All the samples pretreated with enzyme showed a positive effect on organic matter removal (Chemical Oxygen Demand-COD) and formation of methane. The best results were obtained when hydrolysis and biodegradation were performed simultaneously, attaining high COD and color removal independent of the lipase concentration. The enzymatic treatment considerably improved the anaerobic operational conditions and the effluent quality (lower content of suspended solids and less turbidity). Thus, the use of enzymes such as lipase seemed to be a very promising alternative for treating the wastewaters having high fat and grease contents, such as those from the dairy industry.

O presente trabalho teve como objetivo o pré-tratamento de efluente da indústria de laticínios na hidrólise de lipídeos, empregando lipase de fonte de células animais de baixo custo disponível comercialmente (pâncreas de porco) na formação de gás metano por biodegradabilidade anaeróbia empregando diferentes concentrações de lipase (0,05 e 0,5 por cento w.v-1). A utilização de lipase no pré-tratamento do efluente acelerou a hidrólise de lipídeos e, conseqüentemente, auxiliou o tratamento biológico resultando na redução da matéria orgânica em termos de Demanda Química de Oxigênio (DQO), cor e sólidos em suspensão como lipídeos. Os melhores resultados em termos de remoção de DQO e cor foram obtidos quando a hidrólise e biodigestão foram realizadas simultaneamente, independente da concentração de lipase empregada. Estes resultados mostram que a hidrólise e biodigestão podem ser realizadas simultaneamente empregando baixa concentração de lipase (0,05 por cento w.v-1), contribuindo para a redução de custo e tempo no processo de biodegradação aneróbia.

Efeito do tratamento térmico de lodo anaeróbio sobre as características de biodegradabilidade da fração orgânica / Effect of thermal treatment of anaerobic sludge on the biodegradability characteristics of the organic fraction

O presente trabalho avalia o efeito do tratamento térmico do lodo excedente de reatores UASB sobre as características de biodegradabilidade da fração orgânica remanescente, empregando-se o biogás como fonte de energia. O tratamento térmico proporcionou a elevação da temperatura do lodo até valores próximos a 75° C, para tempos de aquecimento de sete horas. Amostras coletadas em diferentes momentos mostraram melhoras significativas na biodegradabilidade do lodo tratado termicamente, com incrementos em 60 vezes para a DBO filtrada, de 30 por cento para a DBO total e 50 por cento para a produção de biogás. Adicionalmente, o retorno do lodo tratado termicamente para o reator UASB não prejudicou as características do efluente.

This paper aimed at evaluating the effect of thermal treatment of excess anaerobic sludge upon the biodegradability characteristics of the remaining organic fraction, using biogas generated in the wastewater treatment process as energy source. Direct burning of the biogas allowed an increase in the sludge temperature up to values close to 75º C, for a seven-hour heating period. Samples taken at different heating times showed significant increase of the biodegradability characteristics of the thermally treated sludge, with augments of around 60 times for filtered BOD, 30 percent for total BOD and 50 percent for biogas production. In addition, no adverse effect on effluent quality was noticed when the thermally treated sludge was returned to the UASB reactor.

Caracterização e biodegradabilidade aeróbia e anaeróbia dos esgotos produzidos em campus universitário / Characterization and biodegradability of wastewater produced in university campus

O presente trabalho caracterizou e avaliou a tratabilidade dos efluentes líquidos produzidos no campus da Universidade Federal de Ouro Preto. Os parâmetros físico-químicos mostraram que o efluente do campus possui uma característica típica a dos esgotos domésticos, com valores médios de DBO5 total, DQO total, NTK e P total de 300 mg.L-1, 670 mg.L-1, 56 mg.L-1 e 6 mg.L-1 respectivamente. Dos metais monitorados somente o Fe (0,847 mg/L), Al (0,355 mg/L) e Zn (0,389 mg/L) estavam presentes em maiores concentrações, mais ainda assim, tais concentrações eram inferiores aos va-lores considerados tóxicos para microrganismos. Os testes de biodegradabilidade mostraram que, a despeito da potencial presença de compostos orgânicos tóxicos, o efluente final pode ser biodegradado aerobiamente (97 por cento de eficiência, K1app = 1,73 d-1) e anaerobiamente (50 por cento de eficiência, AME = 0,0579 gDQO CH4/gSSV.d).

The aim of this study was to characterize and evaluate the tratability of wastewater produced in the campus of the Federal University of Ouro Preto (UFOP). The physical-chemical parameters showed the wastewater from the campus had characteristics of typical domestic wastewater, with average values of total BOD, total COD, Kjeldahl Nitrogen and total phosphorus of 300 mg.L-1, 670 mg.L-1, 56 mg.L-1 e 6 mg.L-1 respectively. Only the metals Fe (0,847 mg/L), Al (0,355 mg/L) and Zn (0,389 mg/L) were present in higher concentration, nonetheless, such concentrations were below the thresholds limits for microbial toxicity. The biodegradability tests showed that despite the potential presence of toxic organic compounds, the wastewater could be degraded aerobically (97 percent efficiency, K1app = 1,73 d-1) and anaerobically (50 percent efficiency, AME = 0,0579 gDQO CH4/gSSV.d).

Biodegradability of commercial and weathered diesel oils

This work aimed to evaluate the capability of different microorganisms to degrade commercial diesel oil in comparison to a weathered diesel oil collected from the groundwater at a petrol station. Two microbiological methods were used for the biodegradability assessment: the technique based on the redox indicator 2,6 - dichlorophenol indophenol (DCPIP) and soil respirometric experiments using biometer flasks. In the former we tested the bacterial cultures Staphylococcus hominis, Kocuria palustris, Pseudomonas aeruginosa LBI, Ochrobactrum anthropi and Bacillus cereus, a commercial inoculum, consortia obtained from soil and groundwater contaminated with hydrocarbons and a consortium from an uncontaminated area. In the respirometric experiments it was evaluated the capability of the native microorganisms present in the soil from a petrol station to biodegrade the diesel oils. The redox indicator experiments showed that only the consortia, even that from an uncontaminated area, were able to biodegrade the weathered diesel. In 48 days, the removal of the total petroleum hydrocarbons (TPH) in the respirometric experiments was approximately 2.5 times greater when the commercial diesel oil was used. This difference was caused by the consumption of labile hydrocarbons, present in greater quantities in the commercial diesel oil, as demonstrated by gas chromatographic analyses. Thus, results indicate that biodegradability studies that do not consider the weathering effect of the pollutants may over estimate biodegradation rates and when the bioaugmentation is necessary, the best strategy would be that one based on injection of consortia, because even cultures with recognised capability of biodegrading hydrocarbons may fail when applied isolated.

Este trabalho objetivou avaliar a capacidade de diferentes microrganismos em degradar óleo diesel comercial em comparação com um óleo diesel intemperizado coletado da água subterrânea em um posto de combustíveis. Dois métodos microbiológicos foram usados para a avaliação da biodegradabilidade: a técnica baseada no indicador redox 2,6-diclorofenol indofenol (DCPIP) e os experimentos respirométricos usando os respirômetros de Bartha. No primeiro, testamos as culturas bacterianas Staphylococcus hominis, Kocuria palustris, Pseudomonas aeruginosa LBI, Ochrobactrum anthropi e Bacillus cereus, um inóculo comercial, consórcios obtidos do solo e da água subterrânea contaminados com hidrocarbonetos e um consórcio de uma área não contaminada. Nos experimentos respirométricos, foi avaliada a capacidade dos microrganismos nativos do solo de um posto de combustíveis em biodegradar os óleos diesel. Os experimentos com o indicador redox mostraram que apenas os consórcios, mesmo aquele de uma área não contaminada, foram capazes de biodegradar o diesel intemperizado. Em 48 dias, a remoção de hidrocarbonetos totais de petróleo (HTP) nos experimentos respirométricos foi aproximadamente 2,5 vezes maior quando o óleo diesel comercial foi usado. Esta diferença foi causada pelo consumo de hidrocarbonetos facilmente biodegradáveis, presentes em maior quantidade no óleo diesel comercial, como demonstrado pelas análises cromatográficas. Assim, resultados indicam que estudos de biodegradabilidade que não consideram o efeito de intemperização dos poluentes pode sobre estimar as taxas de biodegradação e quando o bioaumento é necessário, a melhor estratégia seria aquela baseada na injeção de consórcios, pois mesmo culturas com reconhecida capacidade de biodegradar hidrocarbonetos podem falhar quando aplicadas isoladamente.

Avaliação da biodegradabilidade anaeróbia de lixiviados de aterro sanitários / Evaluate of the anaerobic biodegradability of landfill leachate

Os objetivos deste artigo foram investigar as condições ambientais e operacionais favoráveis ao desenvolvimento do teste de biodegradabilidade anaeróbia para lixiviados de aterro sanitário. As condições avaliadas foram a relação alimento/microrganismo (A/M), aclimatação do lodo, e toxicidade devido à alta concentração de amônia. Os resultados indicaram que a relação A/M equivalente a 0,45 apresentou-se como a mais favorável à realização do teste, e que o lodo empregado apresentou boa capacidade de adaptação ao lixiviado, não demandando aclimatação prévia. O lixiviado em questão apresentou relativamente baixa biodegradabilidade anaeróbia, associado aos resultados de estudos de biodegradabilidade aeróbia anteriores que sugerem que uma significativa fração de matéria orgânica é refratária mesmo ao metabolismo aeróbio,indica que o tratamento físico-químico deve ser utilizado como forma de pré ou pós-tratamento.

The objectives of this article were to investigate the favorable environment and operational conditions to the development of the anaerobic biodegradability test for landfill leachate. The evaluated conditions were the relation food/microrganismo (A/M), seed acclimatization, and toxicity due to high ammonia concentration. The results indicated that A/M relation equivalent to 0,45 was presented as most favorable to the accomplishment of the test, and that the seed used presented good capacity of adaptation to the leachate, not demanding previous acclimatization. The leachate in question presented relatively low anaerobic biodegradability, and associated to the results of previous studies of aerobic biodegradability suggest that a significant fraction of organic substance is refractory to the aerobic and anaerobic metabolism, indicating that the physical-chemical treatment must be used as form of pre or post-treatment.

Evaluation of biodegradability and tissue regenerative potential of synthetic biodegradable membranes / 대한치주과학회지

The purpose of this study was to evaluate on the biodegradability, biocompatibility and tissue regenerative capacity of synthetic biodegradable membranes-Resolut(R), Guidor(R) and Biomesh(R). To evaluate the cell attachment on the membranes, in vitro, the number of gingival fibroblasts attached to each membrane was counted by hemocytometer. Cytotoxicity test for the membranes was performed by MTT test with gingival fibroblast For evaluation of guided bone regenerative potential, the amount of new bone formation in the rat calvarial defects(5mm in diameter) beneath the membranes was observed for two weeks and examined of the specimens by Massons trichrome staining. Biodegradability was observed for 2, 4, 8 and 12 weeks after implantation of each materials under the skin of rats and examined the specimens with H & E staining. The number of cell attachment were the greatest in Biomesh(R) and followed by Resolut(R). Cell viability of three membranes was almost similar levels. Biodegradability of Resolut(R) was the highest among three membrane and the potential of guided bone regeneration was the greatest in the Biomesh(R) and Resolut(R) was followed. These results suggested that commercially available biodegradable membranes were non-toxic and highly potential to guided bone regeneration.

Study on the Biodegradability of Polylactic Acid and the Preparation of Its Microspheres / 中国药房

OBJECTIVE:To study the biodegradability of polylactic acid and prepare its microspheres containing erythromycin.METHODS:The polylactic acid film was degraded in vitro.The orthogonal design was used to optimize the technology of preparation of microspheres.RESULTS:The degradable speed of polylactic acid with high molecular weight was faster than that with low molecular weight.The degradable speed of PDLLA was faster than that of PLLA.The microspheres were stable in quality and regular in external form.The average particle size was (10.98?0.15)?m.The in vitro release properties could be expressed by the Higuchi's equation(Q=28.067+3.8 515 T1/2,r=0.9 834).CONCLUSION:The biodegradability of polylactic acid depended on configuration and molecular weight.Erythromycin microspheres showed significant slow-released property and accorded with the demands of lung targeting agent.