Production, Kinetic/Thermodynamic Study, and Evaluation of the Influence of Static Magnetic Field on Kinetic Parameters of ß-Fructofuranosidase from Aspergillus tamarii Kita UCP 1279 Produced by Solid-State Fermentation.

ß-fructofuranosidases (FFases) are enzymes involved in sucrose hydrolysis and can be used in the production of invert sugar and fructo-oligosaccharides (FOS). This last is an important prebiotic extensively used in the food industry. In the present study, the FFase production by Aspergillus tamarii Kita UCP 1279 was assessed by solid-state fermentation using a mixture of wheat and soy brans as substrate. The FFase presents optimum pH and temperature at 5.0-7.0 and 60 °C, respectively. According to the kinetic/thermodynamic study, the FFase was relatively stable at 50 °C, a temperature frequently used in industrial FOS synthesis, using sucrose as substrate, evidenced by the parameters half-life (115.52 min) and D-value (383.76 min) and confirmed by thermodynamic parameters evaluated. The influence of static magnetic field with a 1450 G magnetic flux density presented a positive impact on FFase kinetic parameters evidenced by an increase of affinity of enzyme by substrate after exposition, observed by a decrease of 149.70 to 81.73 mM on Km. The results obtained indicate that FFases present suitable characteristics for further use in food industry applications. Moreover, the positive influence of a magnetic field is an indicator for further developments of bioprocesses with the presence of a magnetic field.

Enhanced production of prodigiosin by Serratia marcescens UCP 1549 using agrosubstrates in solid-state fermentation.

This work aimed to investigate the production of prodigiosin by S. marcescens UCP 1549 in solid-state fermentation (SSF), as a sustainable alternative for reducing the production costs and environmental impact. Thus, different agro-industrial substrates were used in the formulation of the prodigiosin production medium, obtaining the maximum yield of pigment (119.8 g/kg dry substrate) in medium consisting of 5 g wheat bran, 5% waste soybean oil and saline solution. The pigment was confirmed as prodigiosin by the maximum absorbance peak at 535 nm, Rf 0.9 in TLC, and the functional groups by infrared spectrum (FTIR). Prodigiosin demonstrated stability at different values of temperature, pH and NaCl concentrations and antimicrobial properties, as well as not show any toxicity. These results confirm the applicability of SSF as a sustainable and promising technology and wheat bran as potential agrosubstrate to produce prodigiosin, making the bioprocess economic and competitive for industrial purposes.

Biosurfactant and bioemulsifier as promising molecules produced by Mucor hiemalis isolated from Caatinga soil

BACKGROUND: The present study describes the production of biosurfactant (BS) and emulsifier (BE) by the filamentous fungus Mucor hiemalis UCP 0039, as well as the characterization and stability of the both biomolecules for environmental or industrial applications. RESULTS: Biosurfactants and bioemulsifiers are amphiphilic compounds and are produced as extracellular molecules. The results showed that bioproduct obtained by shaker condition reduced the water surface tension of 72 to 32 mN/m and reached an emulsification index of 96%, while the static cultivation resulted in a biomolecule with a surface tension of 40 mN/m and an emulsification index of 96%, suggesting the production of a biosurfactant and bioemulsifier, respectively. The compounds showed glycolipid nature but the biosurfactant presented cationic charge, while the bioemulsifier, anionic charge. Thus, the results confirmed that M. hiemalis produced two distinct biomolecules under different parameters and in the same culture medium. CONCLUSIONS: It is the first time that biosurfactant and emulsifier production has been described in the same medium and under different physical conditions by Mucor hiemalis. Both biomolecules showed thermal stability, as well as have significant effect on the viscosity of hydrophobic compounds, indicating the excellent potential for environmental safety or industrial applications to improve the efficiency of sustainable and economic technologies.

Economic microbiological conversion of agroindustrial wastes to fungi chitosan.

To investigate the simultaneous influence of different non-nutritional factors in production and physical-chemical characteristics of chitosan obtained by Syncephalastrum racemosum we used individually agroindustrial wastes as the only nutritional sources for fungus growth. The growth conditions were evaluated according to Factorial Design, 24 with three central points in order to determine the mainly factors for maximum production of microbiological chitosan in submerged culture. Syncephalastrum racemosum grown in corn steep liquor and yield up to 7.8 g chitosan/kg of substrate in the best condition by factorial design. The microbiological chitosan obtained has deacetilation degree 88.14%, crystallinity rate of 55.96%, mass decomposition process at 304.43 ºC, and low molecular weight. To fast production we performed a kinetic study and confirmed that at 36 h the chitosan production is higher and the physical-chemical characteristics were maintained. This research describes, for the first time, the factorial study of chitosan production by Syncephalastrum racemosum in agroindustrial wastes and its economic potential for commercialization.

Biotechnological Strategies for Chitosan Production by Mucoralean Strains and Dimorphism Using Renewable Substrates.

We investigated the influence of corn steep liquor (CSL) and cassava waste water (CWW) as carbon and nitrogen sources on the morphology and production of biomass and chitosan by Mucor subtilissimus UCP 1262 and Lichtheimia hyalospora UCP 1266. The highest biomass yields of 4.832 g/L (M. subtilissimus UCP 1262) and 6.345 g/L (L. hyalospora UCP 1266) were produced in assay 2 (6% CSL and 4% CWW), factorial design 22, and also favored higher chitosan production (32.471 mg/g) for M. subtilissimus. The highest chitosan production (44.91 mg/g) by L. hyalospora (UCP 1266) was obtained at the central point (4% of CWW and 6% of CSL). The statistical analysis, the higher concentration of CSL, and lower concentration of CWW significantly contributed to the growth of the strains. The FTIR bands confirmed the deacetylation degree of 80.29% and 83.61% of the chitosan produced by M. subtilissimus (UCP 1262) and L. hyalospora (UCP 1266), respectively. M. subtilissimus (UCP 1262) showed dimorphism in assay 4-6% CSL and 8% CWW and central point. L. hyalospora (UCP 1266) was optimized using a central composite rotational design, and the highest yield of chitosan (63.18 mg/g) was obtained in medium containing 8.82% CSL and 7% CWW. The experimental data suggest that the use of CSL and CWW is a promising association to chitosan production.

Seafood Waste as Attractive Source of Chitin and Chitosan Production and Their Applications.

Chitosan is a cationic polymer obtained by deacetylation of chitin, found abundantly in crustacean, insect, arthropod exoskeletons, and molluscs. The process of obtaining chitin by the chemical extraction method comprises the steps of deproteinization, demineralization, and discoloration. To obtain chitosan, the deacetylation of chitin is necessary. These polymers can also be extracted through the biological extraction method involving the use of microorganisms. Chitosan has biodegradable and biocompatible properties, being applied in the pharmaceutical, cosmetic, food, biomedical, chemical, and textile industries. Chitosan and its derivatives may be used in the form of gels, beads, membranes, films, and sponges, depending on their application. Polymer blending can also be performed to improve the mechanical properties of the bioproduct. This review aims to provide the latest information on existing methods for chitin and chitosan recovery from marine waste as well as their applications.

Biodiversity and phylogeny of novel Trichoderma isolates from mangrove sediments and potential of biocontrol against Fusarium strains.

BACKGROUND: Studies carried out with novel 13 strains of Trichoderma, isolated from mangrove sediments (PE, Brazil) using morphophysiological and molecular characterization, followed evaluation of biocontrol using Fusarium strains isolated from Caatinga soil (PE, Brazil). Trichoderma strains were characterized by polyphasic taxonomic approach, and the extracted DNA was amplified with primers ITS 1 and 4, and sequenced. The biocontrol evaluation was conducted at 24 and 48 h of growth intervals by Tukey test, with a significance of 5%. Antibiosis tests were assessed in vitro by dual plate and partition plate techniques against Fusarium strains. RESULTS: Trichoderma molecular identification, sequences of 500 bp were amplified, deposited into GenBank, and used for phylogenetic analyses. The strains were identified as T. asperellum (10), as T. harzianum (2) and one as T. longibrachiatum. Growth rate presented an average of 0.1207 cm h-1 for Trichoderma and lower growth rate of 0.031 cm h-1 for Fusarium spp., respectively. Antibiosis tests presented the best antagonist level of efficiency for T. asperellum UCP 0149 against F. solani UCP 1395 (82.2%) and F. solani UCP 1075 (70.0%), followed by T. asperellum UCP 0319 against F. solani UCP1083 (73.4%) and T. asperellum UCP 0168 against F. solani UCP1098 (71.5%), respectively. CONCLUSIONS: The data obtained in this study as tool for identification of novel Trichoderma strains serve as basis for development of several sustainable use for biotechnological processes. Those Trichoderma strains found promising for the management antagonistic potential and interaction could aid the conduct of biotechnological biocontrol of contaminants, and improve environmental conditions for the health of plants.

Recovery of chitin and chitosan from shrimp waste with microwave technique and versatile application / Recuperação de quitina e quitosana de resíduos de camarão por micro-ondas e aplicação versátil

In this study, chitin and chitosan were extracted from Litopenaeus vannamei waste using chemical and microwave methods. Shrimp waste was cleaned, dried and ground sieved to 16, 32 and 60 mesh, and the samples were depigmented, demineralized, and deproteinized. Then, the chitin was submitted to a deacetylation process by 45% NaOH solution under microwave irradiation at 600w, for intermittent 15 min or using 5 pulses of 5 minutes. The study showed that the effectiveness of the particle size of 32 mesh and 6 pulses of 5 min to deacetylation with 92% of degree and chitosan yield (52.2%). The polymer chitosan showed higher antimicrobial activity against to Staphylococcus aureus, Escherichia coli, Salmonella enterica and the yeast Candida sp., respectively. The results indicated the feasibility of the microwave radiation as an attractive method to recover chitin and chitosan from shrimp wastes.(AU)

Neste estudo, a quitina e a quitosana foram extraídas de resíduos de Litopenaeus vannamei utilizando métodos químicos e do micro-ondas. Os resíduos de camarão foram limpos, secos e peneirados a 16, 32 e 60 mesh, e as amostras foram despigmentadas, desmineralizadas e desproteinizadas. Posteriormente, a quitina foi submetida a processo de desacetilação por solução de NaOH a 45% sob irradiação de micro-ondas a 600w, durante 15 min intermitentes ou utilizando 6 pulsos de 5 min. O estudo mostrou eficácia nas partículas com tamanho de 32 mesh e 6 pulsos de 5 minutos, com 92% grau de desacetilação e rendimento de quitosana (52,2%). A atividade antimicrobiana foi para Staphylococcus aureus, Escherichia coli e Salmonella enterica contra a levedura Candida sp., respectivamente. Os resultados indicaram a viabilidade da radiação de micro-ondas como um método atraente para recuperação de quitina e quitosana a partir de resíduos de camarão.(AU)

Monohexosylceramides from Rhizopus Species Isolated from Brazilian Caatinga: Chemical Characterization and Evaluation of Their Anti-Biofilm and Antibacterial Activities.

Monohexosylceramides (CMHs) are highly conserved fungal glycosphingolipids playing a role in several cellular processes such as growth, differentiation and morphological transition. In this study, we report the isolation, purification and chemical characterization of CMHs from Rhizopus stolonifer and R. microspores. Using positive ion mode ESI-MS, two major ion species were observed at m/z 750 and m/z 766, respectively. Both ion species consisted of a glucose/galactose residue attached to a ceramide moiety containing 9-methyl-4,8-sphingadienine with an amidic linkage to a hydroxylated C16:0 fatty acid. The antimicrobial activity of CMH was evaluated against Gram positive and Gram negative bacteria using the agar diffusion assay. CMH from both Rhizopus species inhibited the growth of Bacillus terrae, Micrococcus luteus (M. luteus) and Pseudomonas stutzeri (P. stutzeri) with a MIC50 of 6.25, 6.25 and 3.13 mg/mL, respectively. The bactericidal effect was detected only for M. luteus and P. stutzeri, with MBC values of 25 and 6.25 mg/mL, respectively. Furthermore, the action of CMH on the biofilm produced by methicillin-resistant Staphylococcus aureus (MRSA) was analyzed using 12.5 and 25 mg/mL of CMH from R. microsporus. Total biofilm biomass, biofilm matrix and viability of the cells that form the biofilm structure were evaluated. CMH from R. microsporus was able to inhibit the MRSA biofilm formation in all parameters tested.

Biosurfactant production by fungi as a sustainable alternative / Produção de biossurfactantes por fungos como uma alternativa sustentável

A wide variety of bacteria is far more exploited than fungi as biosurfactants (BS) or bioemulsifiers (BE), using renewable sources. BS are considered to be environmentally safe and offer advantages over synthetic surfactants. However, the BS yield depends largely on the metabolic pathways of the microorganisms and the nutritional medium. The production of BS or BE uses several cultural conditions, in which a small change in carbon and nitrogen sources affects the quantity of BS or BE produced. The type and quantity of microbial BS or BE produced depend mainly on the producer organism, and factors such as carbon and nitrogen sources, trace elements, temperature and aeration. The diversity of BS or BE makes it interesting to apply them in the pharmaceutical and cosmetics industries, agriculture, public health, food processes, detergents, when treating oily residues, environmental pollution control and bioremediation. Thus, this paper reviews and addresses the biotechnological potential of yeasts and filamentous fungi for producing, characterizing and applying BS or BE.(AU)

Uma grande variedade de espécies bacterianas é bem mais explorada que os fungos como agentes biossurfactantes (BS) ou bioemulsificantes (BE), usando fontes renováveis. Os BS são considerados ecologicamente seguros e oferecem vantagens sobre os surfactantes sintéticos. Entretanto o rendimento de BS depende grandemente das vias metabólicas dos micro-organismos e do meio nutricional. A produção de BS ou BE utiliza várias condições culturais, em que uma pequena alteração nas fontes de carbono e nitrogênio afeta a produção de BS. O tipo e a quantidade de BS ou BE microbianos produzidos dependem principalmente do organismo produtor e de fatores como fontes de carbono e nitrogênio, oligoelementos, temperatura e aeração. A diversidade de BS ou BE torna-os interessantes para aplicação nos campos farmacêutico, cosmético, da agricultura, da saúde pública, em processos alimentares, detergentes, no tratamento de resíduos oleosos, no controle de poluição ambiental e na biorremediação. Assim, a presente revisão aborda o potencial biotecnológico de leveduras e fungos filamentosos para produção, caracterização e aplicações de BS ou BE.(AU)

Collagenase produced from Aspergillus sp. (UCP 1276) using chicken feather industrial residue.

An extracellular collagenolytic serine protease was purified from Aspergillus sp., isolated from the Caatinga biome in northeast Brazil by a two-step chromatographic procedure, using an anion-exchanger and gel filtration. The enzyme was produced by submerged fermentation of feather residue as a substrate. The purified collagenase showed a 2.09-fold increase in specific activity and 22.85% yield. The enzyme was a monomeric protein with a molecular mass of 28.7 kDa, estimated by an SDS-PAGE and AKTA system. The optimum temperature and pH for enzyme activity were around 40°C and pH 8.0, respectively. The enzyme was strongly inhibited by phenyl-methylsulfonyl fluoride, a serine protease inhibitor, and was thermostable until 65°C for 1 h. We then evaluated the enzyme's potential for degradation of Type I and Type V collagens for producing peptides with antifungal activity. Our results revealed that the cleavage of Type V collagen yielded more effective peptides than Type I, inhibiting growth of Aspergillus terreus, Aspergillus japonicus and Aspergillus parasiticus. Both groups of peptides (Type I and Type V) were identified by SDS-PAGE. To conclude, the thermostable collagenase we purified in this study has various potentially useful applications in the fields of biochemistry, biotechnology and biomedical sciences.

Physicochemical and Antibacterial Properties of Chitosan Extracted from Waste Shrimp Shells.

This research aims to study the production of chitosan from shrimp shell (Litopenaeus vannamei) of waste origin using two chemical methodologies involving demineralization, deproteinization, and the degree of deacetylation. The evaluation of the quality of chitosan from waste shrimp shells includes parameters for the yield, physical chemistry characteristics by infrared spectroscopy (FT-IR), the degree of deacetylation, and antibacterial activity. The results showed (by Method 1) extraction yields for chitin of 33% and for chitosan of 49% and a 76% degree of deacetylation. Chitosan obtained by Method 2 was more efficient: chitin (36%) and chitosan (63%), with a high degree of deacetylation (81.7%). The antibacterial activity was tested against Gram-negative bacteria (Stenotrophomonas maltophilia and Enterobacter cloacae) and Gram-positive Bacillus subtilis and the Minimum Inhibitory Concentrations (MIC) and the Minimum Bactericidal Concentration (MBC) were determined. Method 2 showed that extracted chitosan has good antimicrobial potential against Gram-positive and Gram-negative bacteria and that the process is viable.

Purification of a fibrinolytic protease from Mucor subtilissimus UCP 1262 by aqueous two-phase systems (PEG/sulfate).

A fibrinolytic protease from M. subtilissimus UCP 1262 was recovered and partially purified by polyethylene glycol (PEG)/sodium sulfate aqueous two-phase systems (ATPS). The simultaneous influence of PEG molar mass, PEG concentration and sulfate concentration on the enzyme recovery was first investigated using a 2(3) full factorial design, and the Response Surface Methodology used to identify the optimum conditions for enzyme extraction by ATPS. Once the best PEG molar mass for the process had been selected (6000g/mol), a two-factor central composite rotary design was applied to better evaluate the effects of the other two independent variables. The fibrinolytic enzyme was shown to preferentially partition to the bottom phase with a partition coefficient (K) ranging from 0.2 to 0.7. The best results in terms of enzyme purification were obtained with the system formed by 30.0% (w/w) PEG 6000g/mol and 13.2% (w/w) sodium sulfate, which ensured a purification factor of 10.0, K of 0.2 and activity yield of 102.0%. SDS-PAGE and fibrin zymography showed that the purified protease has a molecular mass of 97kDa and an apparent isoelectric point of 5.4. When submitted to assays with different substrates and inhibitors, it showed selectivity for succinyl-l-ala-ala-pro-l-phenylalanine-p-nitroanilide and was almost completely inhibited by phenylmethylsulfonyl fluoride, behaving as a chymotrypsin-like protease. At the optimum temperature of 37°C, the enzyme residual activity was 94 and 68% of the initial one after 120 and 150min of incubation, respectively. This study demonstrated that M. subtilissimus protease has potent fibrinolytic activity compared with similar enzymes produced by solid-state fermentation, therefore it may be used as an agent for the prevention and therapy of thrombosis. Furthermore, it appears to have the advantages of low cost production and simple purification.

Copper-induced adaptation, oxidative stress and its tolerance in Aspergillus niger UCP1261

Background The effects of exposure to copper, during growth, on the production of biomass, total protein, catalase, glutathione-S transferase, glutathione peroxidase, peroxidase, polyphosphate, acid and alkaline phosphatases, ultrastructure and the ability to remove this metal from Aspergillus niger, obtained from caatinga soil, were evaluated. Results All parameters tested were influenced by the concentration of metal in the culture medium. The presence of metal induced high levels of antioxidant enzymes, including lipid peroxidation, thereby revealing the appearance of an oxidative stress response. The variation in polyphosphate levels indicates the participation of the polymer in response to stress induced by copper. The activities of the phosphatases were positively influenced by growing them in the presence of copper. Ultrastructure changes in the cell surface, electron density, thickness, and septation were visualized by exposing cells to increasingly larger concentrations of metal. The isolate was able to remove the agent from the growth medium, while maintaining its physiological functions. The metal removed from the cultures exposed to 0.5 mM, 1 mM and 2 mM copper exhibited percentages of removal equivalent to 75.78%, 66.04% and 33.51%. Conclusions The results indicate that the isolate was able to grow in high concentrations of copper, activates mechanisms for adaptation and tolerance in the presence of metal, and is highly efficient at removing the agent. Such data are fundamental if a better understanding is to be reached of the cellular and molecular abilities of native isolates, which can be used to develop bioprocesses in environmental and industrial areas.

Isolation and bioelectrochemical characterization of novel fungal sources with oxidasic activity applied in situ for the cathodic oxygen reduction in microbial fuel cells.

Brazilian filamentous fungi Rhizopus sp. (SIS-31), Aspergillus sp. (SIS-18) and Penicillium sp. (SIS-21), sources of oxidases were isolated from Caatinga's soils and applied during the in situ cathodic oxygen reduction in fuel cells. All strains were cultivated in submerged cultures using an optimized saline medium enriched with 10 g L(-1) of glucose, 3.0 g L(-1) of peptone and 0.0005 g L(-1) of CuSO4 as enzyme inducer. Parameters of oxidase activity, glucose consumption and microbial growth were evaluated. In-cell experiments evaluated by chronoamperometry were performed and two different electrode compositions were also compared. Maximum current densities of 125.7, 98.7 and 11.5 µA cm(-2) were observed before 24 h and coulombic efficiencies of 56.5, 46.5 and 23.8% were obtained for SIS-31, SIS-21 and SIS-18, respectively. Conversely, maximum power outputs of 328.73, 288.80 and 197.77 mW m(-3) were observed for SIS-18, SIS-21 and SIS-31, respectively. This work provides the primary experimental evidences that fungi isolated from the Caatinga region in Brazil can serve as efficient biocatalysts during the oxygen reduction in air-cathodes to improve electricity generation in MFCs.

Effects of post-harvest treatment using chitosan from Mucor circinelloides on fungal pathogenicity and quality of table grapes during storage.

The aim of this study was to extract chitosan (CHI) from Mucor circinelloides UCP 050 grown in a corn steep liquor (CSL)-based medium under optimized conditions and to assess the efficacy of the obtained CHI to inhibit the post-harvest pathogenic fungi Aspergillus niger URM 5162 and Rhizopus stolonifer URM 3482 in laboratory media and as a coating on table grapes (Vitis labrusca L.). The effect of CHI coating on some physical, physicochemical and sensory characteristics of the fruits during storage was assessed. The greatest amount of CHI was extracted from M. circinelloides UCP 050 grown in medium containing 7 g of CSL per 100 mL at pH 5.5 with rotation at 180 rpm. CHI from M. circinelloides UCP 050 caused morphological changes in the spores of the fungal strains tested and inhibited mycelial growth and spore germination. CHI coating delayed the growth of the assayed fungal strains in artificially infected grapes, as well as autochthonous mycoflora during storage. CHI coating preserved the quality of grapes during storage, as measured by their physical, physicochemical and sensory attributes. These results demonstrate that edible coatings derived from M. circinelloides CHI could be a useful alternative for controlling pathogenic fungi and maintaining the post-harvest quality of table grapes.

Green conversion of agroindustrial wastes into chitin and chitosan by Rhizopus arrhizus and Cunninghamella elegans strains.

This article sets out a method for producing chitin and chitosan by Cunninghamella elegans and Rhizopus arrhizus strains using a green metabolic conversion of agroindustrial wastes (corn steep liquor and molasses). The physicochemical characteristics of the biopolymers and antimicrobial activity are described. Chitin and chitosan were extracted by alkali-acid treatment, and characterized by infrared spectroscopy, viscosity and X-ray diffraction. The effectiveness of chitosan from C. elegans and R. arrhizus in inhibiting the growth of Listeria monocytogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica, Escherichia coli and Yersinia enterocolitica were evaluated by determining the minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC). The highest production of biomass (24.60 g/L), chitin (83.20 mg/g) and chitosan (49.31 mg/g) was obtained by R. arrhizus. Chitin and chitosan from both fungi showed a similar degree of deacetylation, respectively of 25% and 82%, crystallinity indices of 33.80% and 32.80% for chitin, and 20.30% and 17.80% for chitosan. Both chitin and chitosan presented similar viscosimetry of 3.79-3.40 cP and low molecular weight of 5.08×10³ and 4.68×10³ g/mol. They both showed identical MIC and MBC for all bacteria assayed. These results suggest that: agricultural wastes can be produced in an environmentally friendly way; chitin and chitosan can be produced economically; and that chitosan has antimicrobial potential against pathogenic bacteria.

Effect of corn steep liquor (CSL) and cassava wastewater (CW) on chitin and chitosan production by Cunninghamella elegans and their physicochemical characteristics and cytotoxicity.

Microbiological processes were used for chitin and chitosan production with Cunninghamella elegans UCP/WFCC 0542 grown in different concentrations of two agro-industrial wastes, corn steep liquor (CSL) and cassava wastewater (CW) established using a 2² full factorial design. The polysaccharides were extracted by alkali-acid treatment and characterized by infrared spectroscopy, viscosity, thermal analysis, elemental analysis, scanning electron microscopy and X-ray diffraction. The cytotoxicity of chitosan was evaluated for signs of vascular change on the chorioallantoic membrane of chicken eggs. The highest biomass (9.93 g/L) was obtained in trial 3 (5% CW, 8% CSL), the greatest chitin and chitosan yields were 89.39 mg/g and 57.82 mg/g, respectively, and both were obtained in trial 2 (10% CW, 4% CSL). Chitin and chitosan showed a degree of deacetylation of 40.98% and 88.24%, and a crystalline index of 35.80% and 23.82%, respectively, and chitosan showed low molecular weight (LMW 5.2 × 10³ Da). Chitin and chitosan can be considered non-irritating, due to the fact they do not promote vascular change. It was demonstrated that CSL and CW are effective renewable agroindustrial alternative substrates for the production of chitin and chitosan.

Characterization and properties of the biosurfactant produced by Candida lipolytica UCP 0988

Background: Biotechnological processes are costly, especially for the production of biosurfactants. The successful production of a biosurfactant is dependent on the development of processes using low cost raw materials. Considering the importance of the characteristics of a biosurfactant to facilitate its industrial application, the properties of the biosurfactant produced by Candida lipolytica through previously optimized medium have been established. Results: The yeast was grown for 72 h to determine the kinetics of growth and production. The surface tension of the cell-free broth was reduced from 55 to 25 mN/m. The yield of biosurfactant was 8.0 g/l with a CMC of 0.03%. The biosurfactant was characterized as an anionic lipopeptide composed of 50% protein, 20% lipids, and 8% of carbohydrates. Conclusions: The isolated biosurfactant showed no toxicity against different vegetable seeds: Brassica oleracea, Solanum gilo and Lactuca sativa L. and the micro-crustacean Artemia salina. The properties of the biosurfactant produced suggest its potential application in industries that require the use of effective compounds at low cost.

Effects of chitosan from Cunninghamella elegans on virulence of post-harvest pathogenic fungi in table grapes (Vitis labrusca L.).

This study aimed to obtain chitosan (CHI) from Cunninghamella elegans cultivated in corn step liquid (CSL)-based medium under optimized conditions and to assess the efficacy of the obtained CHI in inhibiting Botrytis cinerea and Penicillium expansum in laboratory media and when applied as a coating on table grapes (Vitis labrusca L.). Moreover, the influence of CHI-based coatings on several physical, physicochemical and sensory characteristics of the fruits during storage was assessed. According to the surface response methodology, the best conditions for isolating CHI from C. elegans cultivated in CSL-medium yielded 8.8 g/100mL at pHs between 5.0 and 5.5 and at 180 rpm. CHI from C. elegans inhibited mycelial growth and spore germination and caused morphological changes in the spores of the tested fungal strains. The CHI coatings delayed the growth of the assayed fungal strains in artificially infected grapes. Applying a CHI coating preserved the quality of grapes, as measured by some physical, physicochemical and sensory attributes, throughout the assessed storage time. These results demonstrate the potential of CHI from C. elegans to control post-harvest pathogenic fungi in fruits, in particular, B. cinerea and P. expansum in table grapes.