RESUMO
Abstract Xylan degradation is an important step in different industries, such as in biorefinery for biomass hydrolysis. Talaromyces wortmannii is a known fungus due to second metabolite production but only few works showed the xylanolytic potential of this fungus. In this way, the aim of this study was to evaluate the production of xylanolytic enzymes from T. wortmannii DR49 on industrial agro wastes. Cultivation in shake flask showed highest xylanase titration (10.3 U/mL; 9.5 U/mL) for wheat bran (WB) and hydrothermal pretreated sugar cane bagasse (HB); in β-xylosidase production WB and xylose were the best carbon sources (0.57 U/mL; 0.34 U/mL) respectively. STR cultivation revealed that 29°C and pH 6.0 were the best conditions for xylanase (14.5 U/mL) and β-xylosidase (1.7 U/mL) production. T. wortmannii DR49 showed to be a potential candidate for xylanolytic enzymes production using agro wastes in bioreactors, which has never been previously reported in this fungus.
RESUMO
Abstract Tailor made enzymatic preparation must be design to hydrolyze efficiently plant biomass, once that each plant biomass possesses a distinct cell wall composition. Most of actinomycetes used for plant cell wall degradation are focused on the cellulases and xylanases production. However, a wide range of enzymes must be produced for an efficient degradation of lignocellulose materials. During the last decade several unusual environments were studied to obtain strains that produce glycohydrolases with innovator characteristics. In this context, the present work concerned the selection of endophytic actinomycetes as producers of hemicellulases and related enzymes with different enzymatic profiles, for use in the deconstruction of lignocellulosic biomass. A total of 45 Brazilian actinomycetes previously isolated from plants (endophytics) and soil were prospected for hemicellulases and β-glucosidase production. Four strains highlighted for hemicellulase production (DR61, DR63, DR69 and DR66) and were selected for cultivation under other inductors substrates (xylan and pectin). All strains belong to Streptomyces genera and have their extracts tested for degradation of several hemicellulolytic substrates. The strains presented different glicohydrolyse enzymes profiles mainly for xylans and glucans that can be used for specific formulations of enzymes applied on the biomass deconstruction, principally on sugar cane bagasse.
Assuntos
Celulase , Actinobacteria , Biomassa , Pectinas , SaccharumRESUMO
The feeding media was studied in a fed-batch process for production of the complex spore-d-endotoxin by B. thuringiensis S93. The microorganism was first cultvated in a initial batch followed by an exponential feeding (m=0,25h(-1)) with concentrated culture media (160 g glucose/L) containing different ratios of glucose and autolysed yeast: 8/7, 8/4 and 8/2 (g/g). The batch culture medium was composed of glucose (8 g/L), autolysed yeast (7g/L) and mineral salts. Sporulation and d-endotoxin production were observed only after the end of feeding. To compare the experiments, batch cultivations were also performed with an initial concentration of 8 g/L of glucose and the same ratio of glucose and autolized yeast. Batch cultivations reached lower concentrations of total biomass and spores than the fed-batch ones and percentagens of sporulation higher than 80 per cente. The 8/7 ratio fed-batch cultivations reached the highest biomass concentration, producing however a very low level of sporulation (27per cent) and virtually no d-endotoxin. Cultivations with 8/4 and 8/2 ratios reached the highest concentrations of spores. In those assays, the maximum spores concentration and the maximum sporulation percentage were 8,3x10(9) spores/mL and 90per cent for the 8/4 ratio and 5,6x10(9) spores/mL and 89per cent for the 8/2 ratio.