Optimized biotransformation of acid-treated water melon peel hydrolyzate into ethanol / Biotransformação otimizada de hidrolisado de casca de melancia tratada com ácido em etanol

Today, global focus of research is to explore the solution of energy crisis and environmental pollution. Like other agricultural countries, bulk quantities of watermelon peels (WMP) are disposed-off in environment as waste in Pakistan and appropriate management of this waste is the need of hour to save environment from pollution. The work emphasizes the role of ethanologenic yeasts to utilize significant sugars present in WMP for low-cost bioethanol fermentation. Dilute hydrochloric acid hydrolysis of WMP was carried out on optimized conditions employing RSM (response surface methodology) following central composite design (CCD). This experimental design is based on optimization of ethanologenesis involving some key independent parameters such as WMP hydrolysate and synthetic media ratio (X1), incubation temperature (X2) and incubation temperature (X3) for maximal ethanol yield exploiting standard (Saccharomyces cerevisiae K7) as well as experimental (Metchnikowia cibodasensisY34) yeasts. The results revealed that maximal ethanol yields obtained from S. cerevisiae K7 was 0.36±0.02 g/g of reducing sugars whereas M. cibodasensisY34, yielded 0.40±0.01 g ethanol/g of reducing sugars. The yeast isolate M. cibodasensisY34 appeared as promising ethanologen and embodies prospective potential for fermentative valorization of WMP-to-bioethanol.

Hoje, o foco global da pesquisa é explorar a solução da crise energética e da poluição ambiental. Como em outros países agrícolas, grandes quantidades de cascas de melancia (WMP) são descartadas como resíduos no meio ambiente no Paquistão, mas a gestão adequada desses resíduos é a mais recente solução para salvar o meio ambiente da poluição. O trabalho enfatiza o papel das leveduras etanologênicas para utilizar açúcares significativos presentes no WMP para fermentação de bioetanol de baixo custo. A hidrólise de ácido clorídrico diluído de WMP foi realizada em condições otimizadas empregando RSM (metodologia de superfície de resposta) e seguindo o projeto de composto central (CCD). Este projeto experimental é baseado na otimização da etanologenesis envolvendo alguns parâmetros independentes importantes, como hidrolisado de WMP e razão de meio sintético (X1), temperatura de incubação (X2) e temperatura de incubação (X3) para rendimento máximo de etanol explorando o padrão (Saccharomyces cerevisiae K7) também como leveduras experimentais (Metchnikowia cibodasensis Y34). Os resultados revelaram que os rendimentos máximos de etanol obtidos a partir de S. cerevisiae K7 foi de 0,36 ± 0,02 g / g de açúcares redutores, enquanto M. cibodasensis Y34 rendeu 0,40 ± 0,01 g de etanol / g de açúcares redutores. O isolado de levedura M. cibodasensis Y34 apareceu como um etanologeno promissor e incorpora um potencial prospectivo para a valorização fermentativa de WMP em bioetanol.

Optimization of the ellagic acid synthesis process at the bioreactor level using non-conventional yeasts

Abstract Ellagic acid (EA) is a phenolic biomolecule. For its biosynthesis, a source of ellagitannins is required, such as strawberries and yeasts, as precursors of the tannase and ß-glucosidase enzymes responsible for hydrolysis of ellagitannins. Two experimental mixture designs were applied., varying the yeast concentration and the number of ellagitannins in the culture medium, evaluating the enzymatic activity and ellagic acid biosynthesis. Aiming to find the optimal compositions of the non-conventional yeasts assessed in the research to biosynthesize ellagic acid feasibly and efficiently using a response surface performing the statistical analysis in the StatGraphics® program for obtaining a higher yield and optimizing the ellagic acid synthesis process, the results indicate that the strains Candida parapsilosis ITM LB33 and Debaryomyces hansenii ISA 1510 have a positive effect on the synthesis of ellagic acid, since as its concentration increases in the mixture the concentration of ellagic acid in the medium also increases; on the other hand, the addition of Candida utilis ITM LB02 causes a negative effect, resulting in the compositions of 0.516876, 0.483124 and 2.58687E-9 respectively, for a treatment under the same conditions, an optimal value of ellagic acid production would be obtained. With an approximate value of 7.33036 mg/mL

Expansion of cord blood stem cells in fibronectin-coated microfluidic bioreactor

ABSTRACT Background: Hematopoietic stem/progenitor cell transplantation is the main treatment option for hematological malignancies and disorders. One strategy to solve the problem of low stem cell doses used in transplantation is pre-transplant expansion. We hypothesized that using fibronectin-coated microfluidic channels would expand HSPCs and keep self-renewal potential in a three-dimensional environment, compared to the conventional method. We also compared stem cell homing factors expression in microfluidic to conventional cultures. Materials and methods: A microfluidic device was created and characterized by scanning electron microscopy. The CD133+ cells were collected from cord blood and purified. They were subsequently cultured in 24-well plates and microfluidic bioreactor systems using the StemSpan serum-free medium. Eventually, we analyzed cell surface expression levels of the CXCR4 molecule and CXCR4 mRNA expression in CD133+ cells cultured in different systems. Results: The expansion results showed significant improvement in CD133+ cell expansion in the microfluidic system than the conventional method. The median expression of the CXCR4 in the expanded cell was lower in the conventional system than in the microfluidic system. The CXCR4 gene expression up-regulated in the microfluidic system. Conclusion: Utilizing microfluidic systems to expand desired cells effectively is the next step in cell culture. Comparative gene expression profiling provides a glimpse of the effects of culture microenvironments on the genetic program of HSCs grown in different systems.

The relationship between methane production metabolic flux and microorganisms in a microbial electrolytic cell coupled anaerobic digestion / 生物工程学报

In this study, voltage was used as a disturbance factor to investigate the relationship between microbial community and methane (CH4) production flux in a microbial electrolytic cell coupled anaerobic digestion (MEC-AD). Metabolic flux analysis (MFA) was used to explore the relationship between the CH4 metabolic flux produced and the microbes. The results showed that both methane production flux and hydrogen production flux changed significantly upon voltage disturbance, while the voltage disturbance had little effect on acetic acid production flux. The maximum CH4 production flux under 0.6 V disturbance was 0.522±0.051, which increased by 77% and 32%, respectively, compared with that of the control group under 1.0 V (0.295±0.013) and under 1.4 V (0.395±0.029). In addition, an average of 15.7%±2.9% of H2 (flux) was used to reduce CO2 to produce CH4 and acetic acid, and an average of 27.7%±6.9% of acetic acid (flux) was converted to CH4. Moreover, the abundance of Lachnospiraceae significantly affected the flux of acetic acid. The flux of CH4 production is positively correlated with the abundances of Petrimonas, Syntrophomonas, Blvii28, and Acinetobacter, and negatively correlated with the abundances of Tuzzerella and Sphaerochaeta. The species that affected the flux of H2 and CH4 were similar, mostly belonging to Bacteroides, Clostridium, Pseudomonas and Firmicutes. Furthermore, the interspecies interaction is also an important factor affecting the MEC-AD methanogenesis flux.

Research progress of combined anaerobic ammonium oxidation (ANAMMOX) process for nitrogen removal / 生物工程学报

Anaerobic ammonia oxidation (ANAMMOX) process is an efficient and low-cost biological nitrogen removal process. However, it still faces some challenges in mainstream applications due to the limitation of substrate types and nitrate accumulation. In recent years, the combined process of anammox has been widely studied to solve the above problems. In this paper, the combined processes of anammox developed in recent years are reviewed, and discussed from the process principle, advantages and disadvantages, influencing factors, process extensibility and the key bottlenecks existing in the promotion and application, as well as the relevant work of the subject group. Finally, we take an outlook on the development of the combined anaerobic ammonia oxidation process in municipal domestic wastewater treatment.

Valuation of angiogenesis in bovine xenografts implanted in intracorporal sites of rabbits as models of in-vivo bioreactors / Avaliação da angiogênese em xenoenxertos bovinos implantados em sítios intracorpóreos de coelhos como modelos de biorreatores in vivo

The aim of this study was to evaluate neovascularization of bovine xenografts implanted in intracorporeal sites of rabbits (bioreactors). 30 rabbits were used, divided into 6 groups, according to the evaluation time (7, 15, 30, 45, and 60 days); each animal received xenogenic implants in 3 different intracorporeal sites (A1 - omentum bag; A2 - intermuscular space of quadriceps femoris; A3 - subperiosteal of ilium bone). Histological assessments graded the presence of angiogenesis, the number of inflammatory cells, newly formed bone tissue, and the presence of giant cells. Histological analyses showed intense angiogenesis in all implanted xenografts. Presence of inflammatory infiltrate and giant cells at the A1 implant site and presence of bone neoformation at the A3 implant site were noted. Degeneration of implants and formation of a fibrous capsule were noted. When comparing the interaction of the site with the days of evaluation, statistical analysis showed a significant difference (p≤0.05) in any time of neovascularization analysis. The vascular endothelial growth factor (VEGF) and inflammatory cells of the omentum in its structure, may have contributed to the greater presence of neovessels and inflammatory cells, a fact that may indicate functionality as a possible bone substitute.(AU)

O objetivo deste estudo foi avaliar a neovascularização de xenoenxertos bovinos implantados em sítios intracorpóreos de coelhos (biorreatores). Foram utilizados 30 coelhos, os quais foram divididos em seis grupos, de acordo com o tempo de avaliação (sete, 15, 30, 45 e 60 dias); cada animal recebeu implantes xenogênicos em três diferentes sítios intracorpóreos (A1 - bolsa de omento; A2 - espaço intermuscular do quadríceps femoral; A3 - subperiosteal do osso ílio). Avaliações histológicas classificaram a presença de angiogênese, o número de células inflamatórias, de tecido ósseo neoformado e a presença de células gigantes. As análises histológicas mostraram intensa angiogênese em todos os xenoenxertos implantados. Observou-se presença de infiltrado inflamatório e células gigantes no local do implante A1 e presença de neoformação óssea no local do implante A3. Ao mesmo tempo, a degeneração dos implantes e a formação de uma cápsula fibrosa foram observadas. Ao comparar a interação do local com os dias de avaliação, a análise estatística mostrou diferença significativa (P≤0,05) em qualquer momento da análise de neovascularização. O fator de crescimento endotelial vascular (VEGF) e as células inflamatórias do omento em sua estrutura podem ter contribuído para a maior presença de neovasos e células inflamatórias, fato que pode indicar funcionalidade como possível substituto ósseo.(AU)

Media development and process parameter optimization using statistical experimental designs for the production of nonribosomal peptides in Escherichia coli

BACKGROUND: Nonribosomal peptide synthases (NRPS) can synthesize functionally diverse bioactive peptides by incorporating nonproteinogenic amino acids, offering a rich source of new drug leads. The bacterium Escherichia coli is a well-characterized production host and a promising candidate for the synthesis of nonribosomal peptides, but only limited bioprocess engineering has been reported for such molecules. We therefore developed a medium and optimized process parameters using the design of experiments (DoE) approach. RESULTS: We found that glycerol is not suitable as a carbon source for rhabdopeptide production, at least for the NRPS used for this study. Alternative carbon sources from the tricarboxylic acid cycle achieved much higher yields. DoE was used to optimize the pH and temperature in a stirred-tank reactor, revealing that optimal growth and optimal production required substantially different conditions. CONCLUSIONS: We developed a chemically defined adapted M9 medium matching the performance of complex medium (lysogeny broth) in terms of product concentration. The maximum yield in the reactor under optimized conditions was 126 mg L-1, representing a 31-fold increase compared to the first shaking-flask experiments with M9 medium and glycerol as the carbon source. Conditions that promoted cell growth tended to inhibit NRPS productivity. The challenge was therefore to find a compromise between these factors as the basis for further process development.

Biorreactores de un solo uso en la industria biofarmacéutica y su uso en la producción de candidatos vacunales contra SARS- COV-2. Artículo de revisión / Single-use systems bioreactors in the biopharmaceutical industry and its use in SARS-CoV-2 vaccine's candidates production. A review

Los biorreactores de sistemas de un solo uso (SUSs), también conocidos como biorreactores desechables, se han convertido en una parte integral de las instalaciones biotecnológicas de fabricación para bioproductos con un mercado potencial que espera una tasa de crecimiento de casi el 15,5% durante el período pronosticado: 2018 a 2023. Los biorreactores SUSs son más seguros, simples y flexibles al compararlos con sus contrapartes, biorreactores de acero inoxidable, por lo que su uso se está incrementando en la industria biofarmacéutica principalmente en la planificación de vías rápidas de proyectos complejos, incluidos los relacionados con la pandemia de SARS-CoV-2. Así, el uso de SUS se ha convertido en una alternativa eficaz para la producción rápida de candidatos a vacunas. Pero algunas desventajas técnicas y operativas aún obstaculizan su uso en todo el mundo. Esta revisión brinda una visión racional del uso, los tipos, los parámetros operativos y las nuevas aplicaciones de los biorreactores SUSs en la industria biofarmacéutica. Asimismo, también se discuten los parámetros apropiados y las limitaciones de este equipo, enfocándose en su uso para la producción de vacunas contra COVID-19

Single-Use-Systems (SUSs) Bioreactors, also known as disposable bioreactors, have become an integral part of biotechnology manufacturing facilities for bioproducts with a potential market expecting a growth rate of nearly 15.5% over the forecast period: 2018 to 2023. SUSs bioreactors are comparatively safe, simple, and flexible than their stainless-steel bioreactors counterparts thus, their usage is being augmented in the biopharmaceutical industry mainly in planning fast tracks of complex projects, including those related to the SARS-CoV-2 pandemic. Thus, the use of SUSs has become an effective alternative for the rapid production of vaccine candidates. However, some technical and operational disadvantages still hamper their worldwide use. This review gives a rational insight into SUSs bioreactors use, types, operational parameters and new applications in the biopharmaceutical industry. Likewise, the appropriate parameters and limitations of this equipment, focusing on its use for vaccine production against COVID-19 are also discussed

Microorganisms in the typical anaerobic digestion system of organic solid wastes: a review / 生物工程学报

The facultative anaerobic and strict anaerobic microorganisms enriched and acclimated during the anaerobic digestion process are crucial for the efficiency of the anaerobic digestion system. Most of the problems encountered during running anaerobic digestion processes could be effectively improved via stimulation of microbial metabolic activity. Benefited from the rapid development of microbiome techniques, deeper insights into the microbial diversity in anaerobic digestion systems, e.g. the microbe-microbe interactions and microbe-environment interactions, have been gained. A complex and intricate metabolic network exists in the anaerobic digestion system of solid organic wastes. However, little is known about these interactions and the underlying mechanisms. This review briefly summarized the representative interactions between microbial communities during anaerobic digestion process discovered to date. In addition, typical issues encountered during the anaerobic digestion of solid organic wastes and how microbes can tackle and alleviate these issues were discussed. Finally, future priorities on microbiome research were proposed based on present contribution of microbiome analysis in anaerobic digestion system.

New opportunities and challenges for hybrid data and model driven bioprocess optimization and scale-up / 生物工程学报

Currently, biomanufacturing technology and industry are receiving worldwide attention. However, there are still great challenges on bioprocess optimization and scale-up, including: lacing the process detection methods, which makes it difficult to meet the requirement of monitoring of key indicators and parameters; poor understanding of cell metabolism, which arouses problems to rationally achieve process optimization and regulation; the reactor environment is very different across the scales, resulting in low efficiency of stepwise scale-up. Considering the above key issues that need to be resolved, here we summarize the key technological innovations of the whole chain of fermentation process, i.e., real-time detection-dynamic regulation-rational scale-up, through case analysis. In the future, bioprocess design will be guided by a full lifecycle in-silico model integrating cellular physiology (spatiotemporal multiscale metabolic models) and fluid dynamics (CFD models). This will promote computer-aided design and development, accelerate the realization of large-scale intelligent production and serve to open a new era of green biomanufacturing.

Co-fermentation of kitchen waste and excess sludge for organic acid production: a review / 生物工程学报

Resource utilization is an effective way to cope with the rapid increase of kitchen waste and excess sludge, and volatile fatty acids produced by anaerobic fermentation is an important way of recycling organic waste. However, the single substrate limits the efficient production of volatile fatty acids. In recent years, volatile fatty acids produced by anaerobic co-fermentation using different substrates has been widely studied and applied. In this paper, we analyze the characteristics of fermentation to produce acid using kitchen waste and excess sludge alone or mixture. Influences of environmental factors and microbial community structure on the type and yield of volatile fatty acids in the anaerobic fermentation system are discussed in detail. Moreover, we propose future research directions, to provide a reference for recycling kitchen waste and excess sludge.

A review on polyhydroxyalkanoates synthesis in activated sludge system: the effects of dissolved organic compounds by using anaerobic fermentation liquid from waste activated sludge / 生物工程学报

Polyhydroxyalkanoates (PHA) synthesis by activated sludge using volatile fatty acids (VFAs) in fermentation liquid of excess sludge as carbon source is a hotspot in the field of environmental biotechnology. However, there is no unified conclusion on the effects of non-VFAs, mainly dissolved organic matter (DOM), on PHA production. Thus, this critical review mainly introduces the main characteristics and common analysis methods of DOM in anaerobic fermentation liquid. The effects of DOM on PHA production are analyzed from the aspects of microbiology, metabolic regulation and sludge properties. The results of different studies showed that high concentration of DOM is bad for PHA production, but an appropriate amount of DOM is conducive to the stability of sludge properties, reducing the final PHA purification cost. Finally, suitable strategies were proposed to regulate the PHA synthesis by activated sludge with DOM for PHA production by anaerobic fermentation liquid.

Enhanced pyruvic acid yield in an osmotic stress-resistant mutant of Yarrowia lipolytica

BACKGROUND: Pyruvic acid (PA), a vital α-oxocarboxylic acid, plays an important role in energy and carbon metabolism. The oleaginous yeast Yarrowia lipolytica (Y. lipolytica) has considerable potential for the production of PA. An increased NaCl concentration reportedly increases the biomass and PA yield of Y. lipolytica. RESULTS: To increase the yield of PA, the NaCl-tolerant Y. lipolytica A4 mutant was produced using the atmospheric and room temperature plasma method of mutation. The A4 mutant showed growth on medium containing 160 g/L NaCl. The PA yield of the A4 mutant reached 97.2 g/L at 120 h (0.795 g/g glycerol) in a 20-L fermenter with glycerol as the sole carbon source, which was 28.9% higher than that of the parental strain. CONCLUSION: The PA yield from Y. lipolytica can be improved by increasing its NaCl tolerance.

Release of formaldehyde during the biofiltration of methanol vapors in a peat biofilter inoculated with Pichia pastoris GS115

BACKGROUND: Methanol can be effectively removed from air by biofiltration (Shareefdeen et al., 1993; Babbitt et al., 2009 [1,2]). However, formaldehyde is one of the first metabolic intermediates in the consumption of methanol in methylotrophic microorganisms (Negruta et al., 2010 [3]), and it can be released out of the cell constituting a secondary emission. RESULTS: The total removal of methanol was achieved up to input loads of 263 g m−3 h−1 and the maximum elimination capacity of the system was obtained at an empty bed residence times of 90 s and reached 330 g m−3 h−1 at an input methanol load of 414 g m−3 h−1 and 80% of removal efficiency. Formaldehyde was detected inside the biofilter when the input methanol load was above 212 g m−3 h−1 . Biomass in the filter bed was able to degrade the formaldehyde generated, but with the increase of the methanol input load, the unconsumed formaldehyde was released outside the biofilter. The maximum concentration registered at the output of the system was 3.98 g m−3 when the methanol load was 672 g m−3 h−1 in an empty bed residence times of 60 s. CONCLUSIONS: Formaldehyde is produced inside a biofilter when methanol is treated in a biofiltration system inoculated with Pichia pastoris. Biomass present in the reactor is capable of degrading the formaldehyde generated as the concentration of methanol decreases. However, high methanol loads can lead to the generation and release of formaldehyde into the environment.

Development and optimization of perfusion process for mammalian cell culture / 生物工程学报

In recent years, the demand of biologics has increased rapidly. Cell culture process with perfusion mode has become more and more popular due to its high productivity, good quality and high efficiency. In this paper, the unique operation and the details of process optimization for perfusion culture mode are discussed by comparing with traditional batch culture process. Meanwhile, the progress and strategies in the development and optimization of perfusion culture process in recent years are summarized to provide reference for the future development of mammalian cell perfusion culture technology.

Numerical simulation and optimization of impeller combination used in stirred bioreactor / 生物工程学报

Bioreactors have been central in monoclonal antibodies and vaccines manufacturing by mammalian cells in suspension culture. Numerical simulation of five impeller combinations in a stirred bioreactor was conducted, and characteristics of velocity vectors, distributions of gas hold-up, distributions of shear rate in the bioreactor using 5 impeller combinations were numerically elucidated. In addition, genetically engineered CHO cells were cultivated in bioreactor installed with 5 different impeller combinations in fed-batch culture mode. The cell growth and antibody level were directly related to the maximum shear rate in the bioreactor, and the highest viable cell density and the peak antibody level were achieved in FBMI3 impeller combination, indicating that CHO cells are sensitive to shear force produced by impeller movement when cells were cultivated in bioreactor at large scale, and the maximum shear rate would play key roles in scaling-up of bioreactor at industrial scale.

Effect of microbial community structure of activated sludge in an Anaerobic-anoxic-oxic process with Actinic reaction enzyme system start-up / 生物工程学报

In order to explore the microbial communities and functions of activated sludge in an Anaerobic-anoxic-oxic (A²/O) process under the start-up of Actinic reaction enzyme system (ARES) system and to understand the impact of the ARES system in domestic sewage treatment process, the activated sludge microbial community structure in the A²/O process system before and after ARES system start-up was analyzed by Illumina-HiSeq 2000 high-throughput sequencing platform. By combining with the main parameters related to the effect of sewage treatment, we analyzed the environmental functions of the microbial communities. The microbial community structure of activated sludge was significantly different before and after the ARES system start-up. There were 9 main bacterial phyla in the system (average relative abundance ≥1%), accounting for 96%-98% of the total bacteria sequenced. After the ARES system was started, the relative abundance of Betaproteobacteria and Chlorobi increased by 3.45%-3.85% and 0.45%-2.61%, respectively. In the anaerobic unit, the relative abundance of Bacteroidetes increased by 12.97%, while the Actinobacteria and Firmicutes decreased by 9.60% and 1.45%, respectively. At the genus level of bacteria, the relative abundance of Denitratisoma increased by 0.80%-3.27%, while the Haliangium and Arcobacter decreased by 3.36%-4.52% and 1.48%-3.45%, respectively. The relative abundance of bacteria was significantly different before and after the ARES system start-up. There were 7 abundant fungi phyla (average relative abundance ≥1%) in the system. After the ARES system was started, the relative abundance of Rozellomycota decreased by 42.71%-46.77%. In the anaerobic unit, the relative abundance of Ascomycota decreased by 13.39%, while the relative abundance of Glomeromycota increased by 13.86%. At the genus level of fungi. The relative abundance of Entomophthoraceae sp. and Glomcromycota sp. increased by 31.35%-36.50% and 6.27%-13.84%, respectively, while the Rozellomycota sp. and Xylochrysis lucida decreased by 42.71%-46.77% and 3.67%-5.54%, respectively. Our results showed that the application of ARES system caused the response of the microbial community to environmental changes, especially for the fungi communities, in the meanwhile, improved the effluent quality, especially the removal rate of total nitrogen.

Application of micro- and mini-bioreactors in biomedicine development and production / 生物工程学报

Micro- and mini-bioreactors are characterized by their miniature working volume and comprehensive monitoring of process data, e.g., biomass, pH, dissolved oxygen, and fluorescence that are on par with conventional bench-top systems. The technical advancements of micro- and mini-bioreactors are supported by single-use material and micro-manufacturing, non-invasive optical sensors, automation such as industrial robotics and the integration of design of experiment software with data acquisition and process control. Owing to the miniature scales, micro-bioreactors typically feature lower turbulence intensity and energy dissipation rate, resulting in different mass transfer, mixing and shear conditions as compared to industrial scale equipment. Mini-bioreactors, nevertheless, are closer to large vessels. Micro- and mini-bioreactors are used mostly in screening and process development nowadays, owing to their combined high throughput and richness of data. They are also the hardware that will enable "precision medicine" in the near future.

Influence of Landfill Leachate on Organic Matter Removal in Activated Sludge and Activated Sludge with Carrier Processes

Abstract This study assessed the performance of two pilot units, a conventional activated sludge (CAS) and an Integrated Fixed-Film Activated Sludge (IAS), in the treatment of leachate from sanitary landfill combined with domestic sewage, with the aim of removing organic substances. In order to assess the possible impacts on treatment, three experimental phases were designed using influent leachate contributions of 5%, 10%, and 20% of the total BOD load. Overall, the results showed that no significant changes in the behavior of biological processes. The IAS unit presented average BOD removal efficiencies of above 88%, 87% and 80% for the three leachate load contributions of 5%, 10% and 20% studied. The CAS unit presented lower average efficiency with a 5% leachate contribution (64%), but displayed a similar performance to the IAS unit in the other phases (82% and 80%); similar quantitative aspects were observed for both treatment processes with regards to biomass composition analysis. The kinetic coefficients related to heterotrophic metabolism did not indicate negative effects on treatment efficiency as a result of the increase in leachate addition, with values of 2.8; 2.8 and 2.7 d-1 obtained respectively for each phase with the CAS unit, and 2.0; 1.5 and 1.6 d-1 with the IAS unit, representing similar values to those found in the literature (1.5 a 5.0 d-1). The results reinforced the conclusion that the leachate load introduced did not cause inhibition or significant alterations to heterotrophic metabolism, and, therefore, to the removal of organic matter.

Evaluation of a Combined System Based on an Upflow Anaerobic Sludge Blanket Reactor (UASB) and Shallow Polishing Pond (SPP) for Textile Effluent Treatment

Abstract Color removal from textile effluents was evaluated using a laboratory-combined process based on an upflow anaerobic sludge blanket (UASB) reactor followed by a shallow polishing pond (SPP). The anaerobic reactor was fed with a real textile effluent, diluted 10-times in a 350 mg/L solution of pre-treated residual yeast extract from a brewery industry as nutrient source. The parameters color, COD, N-NH3 and toxicity were monitored throughout 45 days of operation. According to the results, decolorization and COD removal were highest in the anaerobic step, whereas the effluent was polished in the SPP unit. The overall efficiency of the complete UASB-SPP system for COD and color were 88 and 62%, respectively. Moreover, the N-NH3 generated by the residual yeast extract ammonification was below 5 mg/L for the final effluent. Finally, no toxicity was detected after the treatment steps, as shown by the Vibrio fischeri microscale assay.