No abstract

Activity levels of extracellular hydrolytic enzymes produced by Stenocarpella maydis, a fungal pathogen of maize, have so far not been reported. Production of xylanase, cellulase, and acid protease by this ascomycete using different culture media in solid-state and submerged fermentation was studied. In solid-state fermentation, polyurethane foam was used as an inert support, and corncob, corn leaves, and broken corn were used as biodegradable supports. The highest xylanase activity was produced in the medium with xylan in both fermentation systems, reaching 18,020 U/L and 19,266 U/L for submerged and solid-state fermentation, respectively. Cellulase production was observed only in the culture medium with carboxymethylcellulose, obtaining values of 7,872 U/L in submerged fermentation and 9,439 U/L in solid-state fermentation. The acid protease was produced only in minimal medium with glucose in acidic pH, reaching the highest levels of activity in SSF (806 U/L). The corncob was the best biodegradable support for the production of xylanases and acid protease. Two isoenzymes of xylanase and cellulase were observed in both fermentation systems, and three isoenzymes of xylanase were produced on the biodegradable supports.

No abstract

In this study, the induction of esterase activity during the degradation of a high concentration of di(2-ethylhexyl) phthalate (DEHP) (1500 mg l −1 ) by Fusarium culmorum was investigated using Ca(NO 3 ) 2 as nitrogen source under liquid fermentation conditions. Assessments of esterase activities through biochemical tests and zymographic assays, as well as fungal growth were studied. A high concentration of DEHP increased esterase activity in F. culmorum, which produces five esterase isoforms (26.4, 31.7, 43, 73.6 and 125 kDa), which were different in abundance and molecular weight to those produced constitutively in glucose-containing medium (control medium). F. culmorum showed higher µ and Y X/S values in DEHPcontaining medium than those observed in the control medium. F. culmorum has great potential for use in the restoration of sites contaminated with high concentrations of DEHP and even of other phthalates with less complex structures.

Cutinolytic esterase (i.e., cutinase) is an enzyme that catalyzes the cleavage of ester bonds in cutin and also in diverse soluble and insoluble esters. It has application in several biotechnological areas, acting as biocatalysts in the food industry, in detergents, in biodegradation of polymers and other toxic substances, being important in biorremediation. In this research, specific growth rate, protein content, cutinolytic activity by biochemical tests and polyacrylamide gel electrophoresis, and growth and enzymatic kinetic parameters were determined for F. culmorum grown at different apple cutin concentrations (0.2, 2 and 20 g/L) in submerged fermentation. It was observed that biomass, protein content and enzymatic activity enhanced as cutin concentration increased in the media. A cutinase activity band of around 65 KDa was observed in zymograms of different cutin concentration. An additional cutinase activity band of around 90 KDa was also observed in zymograms of F. culmorum grown in 20 g of apple cutin/L. These studies showed that F. culmorum used apple cutin as the sole carbon source, which acted as a cutinase inducer. The highest-yielding parameters of cutinase were observed in 2 g of apple cutin/L. This research showed promising results in the cutinase induction for F. culmorum using a low concentration of apple cutin.