Novel production of biodispersant by Serratia marcescens UCP 1549 in solid-state fermentation and application for oil spill bioremediation.

Oil spills in aquatic ecosystems cause irreparable damage to marine life and the coastal populations of affected areas. In recent years, chemical dispersants have been extensively used to remedy these impacted ecosystems, although these agents have been increasingly restricted due to their toxic potential. In this context, biosurfactants are emerging as a promising alternative to chemical dispersants, which have some advantages including low toxicity, high biodegradability and good ecological acceptability. Thus, this study aimed to the production of biosurfactant by the bacteria Serratia marcescens UCP 1549 for application as biodispersant. The experiment was carried out using wheat bran as substrate in solid-state fermentation (SSF) as low-cost technology. Biosurfactant production was verified by the reduction of surface tension (28.4 mN/m) and interfacial tension (4.1 mN/m) with n-hexadecane. Also, promising result of emulsification (94%) with burned motor oil was obtained. Acid precipitation yielded 52.0 g/kg dry substrate of biosurfactant, that was identified as an anionic compound of a lipopeptide nature by the Zeta potential and FTIR spectrum, respectively. The biomolecule showed stability under extreme conditions of temperature, pH and salinity, as well as low toxicity against the microcrustacean Artemia salina. In addition, the biosurfactant demonstrated excellent properties to dispersing burned motor oil in water (ODA = 50.24 cm2) and to washing of marine stones (100% removal of burned motor oil). Therefore, these results confirm SSF as a sustainable technology for the production of biodispersant by S. marcescens UCP 1549, promising in the bioremediation of marine ecosystems impacted by petroderivatives.

Ultrasound pretreatment application in dehydration: its influence on the microstructure, antioxidant activity and carotenoid retention of biofortified Beauregard sweet potato (Ipomoea batatas Lam).

This work aimed to evaluate the effects of ultrasound pretreatment on the microstructure, antioxidant activity, and carotenoid retention of biofortified Beauregard sweet potato (BBSP). The pretreatment was carried out in an ultrasonic bath at 30 °C for 10 min, and it was evaluated in terms of water loss and solid gain. The drying process was performed at two different temperatures (50 and 70 °C). Six different semi-theoretical mathematical models were examined to characterize the drying curves, and quality analyses were executed. The two-terms exponential model provided the best simulation of the drying curves. Drying time was reduced by performing ultrasound pretreatment and by increasing drying temperature. The ultrasound treatment caused greater agglomeration, breakage, or strangulation of the BBSP structure, increasing porosity, and thus increasing drying rates. Drying caused a diminution of total carotenoids content and influenced antioxidant activity. However, the samples pretreated with ultrasound and dried produced lower total carotenoids loss.

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.

Chitosan-citric acid edible coating to control Colletotrichum gloeosporioides and maintain quality parameters of fresh-cut guava.

This study aimed to verify the action of edible chitosan-citric acid (CHI-CA) coating to control Colletotrichum gloeosporioides and maintain quality parameters of fresh-cut guava. Chitosan was obtained from Litopenaeus vannamei shells using high temperature and short exposure times. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of CHI-CA against C. gloeosporioides were determined by macrodilutions at 28 °C/120 h in the absence/presence of CHI-CA (0-10 mg/mL). Scanning electron microscopy was used to evaluate morphological changes in the fungus. Guava slices were coated with CHI-CA (MIC) or 5 mg/mL glycerol (control). Rot incidence and physicochemical, physical, and microbiological factors were determined at 0, 3, 7, and 14 days at 24 °C and 4 °C. Chitosan presented typical structural characterization, 64% deacetylation, and a molecular weight of 1.6 × 104 g/mol. CHI-CA exhibited MIC and MFC values of 5 mg/mL and 10 mg/mL, respectively, and promoted changes in the morphology and cell surface of fungal spores. The fresh-cut guava coated with CHI-CA maintained quality parameters during storage and preserved their sensorial characteristics. Therefore, the use of CHI-CA as a coating is a promising strategy for improving postharvest quality of fresh-cut fruits.

Agroindustrial waste as ecofriendly and low-cost alternative to production of chitosan from Mucorales fungi and antagonist effect against Fusarium solani (Mart.) Sacco and Scytalidium lignicola Pesante.

This study aimed to evaluate the production of fungal chitosan (FuChi) from Mucorales fungi cultivated in a cashew apple juice (CAJ) and cheese whey (CW) mixture, and to determine the growth-inhibitory effect of this biopolymer against Fusarium solani CFF109 and Scytalidium lignicola CMM1098, which cause root rot disease in cassava plants. Cunninghamella phaeospora UCP 1303 and Cunninghamella elegans UCP 1306 showed the highest FuChi production in screening assay, being selected to a CCRD 22 design to analyze the influence of different CAJ and CW concentrations in the increase of FuChi production. All nine Mucorales fungi cultivated in CAJ-CW medium, showing FuChi production in the range of 27.58 (Mucor hiemalis UCP 1309) to 65.40 mg/g (C. elegans UCP 1306). During CCRD 22 design, the highest FuChi production (64.09 mg/g) was achieved by C. elegans UCP 1306 cultivated in medium containing 40% (v/v) of CAJ and 30% (v/v) of CW, presenting 75% deacetylation degree and crystallinity indexes of 41.50%. FuChi at 16000 µg/mL showed a better inhibition against S. lignicola mycelial growth (81.70%) when compared with F. solani (22.13%) and induced alterations in hyphae morphology on both strains. CAJ and CW are promising substrates for FuChi production, and this biopolymer shows antimicrobial effect against F. solani and S. lignicola.

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.

Chitosan produced from Mucorales fungi using agroindustrial by-products and its efficacy to inhibit Colletotrichum species.

This study evaluated corn steep liquor (CSL) and papaya peel juice (PPJ) in mixture as substrates for the cultivation (96h, 28°C, pH 5.6, 150rpm) of Mucorales fungi for chitosan production, and determined the growth-inhibitory effect of the fungal chitosan (FuCS) obtained under optimized conditions against phytopathogenic Colletotrichum species. All Mucorales fungi tested were capable of growing in CSL-PPJ medium, showing FuCS production in the range of 5.02 (Fennelomyces heterothalicus SIS 28) - 15.63mg/g (Cunninghamella elegans SIS 41). Highest FuCS production (37.25mg/g) was achieved when C. elegans was cultivated in medium containing 9.43% CSL and 42.5% PPJ. FuCS obtained under these conditions showed a deacetylation degree of 86%, viscosity of 120cP and molecular weight of 4.08×104g/mol. FuCS at 5000, 7500 and 10,000ppm inhibited the growth of all Colletotrichum species tested. FuCS also induced alterations in the morphology of C. fructicola hyphae. CSL-PPJ mixtures are suitable substrates for the cultivation of Mucorales fungi for FuCS production. Chitosan from C. elegans cultivated in CSL-PPJ medium is effective in inhibiting phytopathogenic Colletotrichum species.

Role of the morphology and polyphosphate in Trichoderma harzianum related to cadmium removal.

This study concerns the metabolism of polyphosphate in Trichoderma harzianum, a biocontrol agent with innate resistance against most chemicals used in agriculture, including metals, when grown in the presence of different concentrations of cadmium. The biomass production was affected by the concentration of metal used. Control cultures were able to accumulate polyphosphate under the conditions used. Moreover, the presence of cadmium induced a reduction in polyphosphate content related to the concentration used. The morphological/ultrastructural aspects were characterized by using optical and scanning electron microscopy, and were affected by the heavy metal presence and concentration. The efficiency of cadmium removal revealed the potential of the microorganism for use in remediation. The data indicate the potential for polyphosphate accumulation by the fungus, as well as its degradation related to tolerance/survival in the presence of cadmium ions.

Copper influence on polyphosphate metabolism of Cunninghamella elegans

O presente trabalho teve como finalidade avaliar os aspectos fisiológicos do metabolismo do polifosfato em Cunninghamella. elegans cultivada em meio contendo cobre. O perfil de crescimento foi estabelecido em função da produção de biomassa, consumo de ortofosfato, acumulação de polifosfato e atividade das fosfatases. Os resultados obtidos indicaram a influência do metal pesado sobre o crescimento, como observado pelo rendimento da biomassa. O consumo da fonte de fósforo durante as primeiras 24 horas de crescimento na cultura tratada com cobre foi maior que na cultura controle. A acumulação de polifosfato permitiu verificar comportamentos distintos na ausência e presença do metal. A análise do polifosfato celular revelou que, nas amostras tratadas, o polímero é significativamente metabolizado durante o início do cultivo quando em presença do cobre. O isolado analisado não exibiu atividade para a fosfatase ácida. Contudo, o cultivo em presença de cobre induziu variações na expressão da enzima fosfatase alcalina. Uma diminuição significativa da atividade enzimática foi observada para a cultura tratada com o íon metálico. Os estudos demonstram o potencial de Cunninghamella elegans para biorremediação de ambientes contaminados com cobre.

Effects of phosphorus on polyphosphate accumulation by Cunninghamella elegans

O crescimento, consumo de fosfato e glicose, bem como o conteúdo de fósforo, a distribuicão, estrutura e localizacão de polifosfato foram avaliados no micélio de Cunninghamella elegans cultivado em meios contendo diferentes concentracões de fosfato. Os resultados permitiram verificar a influência dessas concentracões de fosfato sobre o crescimento do fungo estudado. A maior concentracão de fosfato proporcionou maior rendimento da biomassa ao longo do crescimento. Uma relacão entre consumo de fosfato e glicose do meio foi observada em relacão ao crescimento e a quantidade de polifosfato total nos micélios cultivados nos diferentes meios de cultivo. Distintos métodos de extracão permitiram identificar e quantificar as diferentes fracões do polifosfato celular de Cunninghamella elegans. A citoquímica ultrastrutural foi utilizada com sucesso para identificar a localizacão e a distribuicão de polifosfato em Cunninghamella elegans. Os resultados revelaram diferencas no padrão de marcacão citoquímica nas diferentes fases do crescimento e meios de cultivo. Uma marcacão uniforme do polifosfato foi observada sobre a superfície celular, em especial, na parede celular e na membrana citoplasmática. Produtos de reacão resultantes da marcacão citoquímica foram também visualizados em estruturas trabeculares, vacuolares, vesiculares, sob a forma de corpos eletrondensos e grânulos dispersos no citoplasma. Os resultados demonstraram o potencial de Cunninghamella elegans na acumulacão de polifosfato, sugerindo uma possível aplicacão em processos biotecnológicos.