Xylanases and cellulases biosynthesis by selected fungi in a simple and economic bio system using sugarcane straw

Abstract

Sugarcane straw (SS) was used in an economic biosystem to evaluate the production of xylanases and cellulases in submerged fermentation (SmF) by axenic and mixed mode from Trichoderma and Aspergillus species. T. reesei QM9414 axenic culture reached the highest xylanase production (90.2 U/mL) and 0.5 FPU/mL of cellulase activity. The evaluation of agro-industrial residues on fibrolytic enzymes production was performed by a D-optimal design, and revealed the best supplementation of 100% SS, while wheat bran and citric pulp showed lower inductive effects on enzymes production. Also, the scale-up in a stirred tank showed the same yield production profile (xylanase ~ 90 U/mL and celullase 0.6 FPU/mL). Xylanase was characterized by an optimum pH of 5-6 and temperature at 50 ºC, and thermal stability was below 50 ºC. The ion Mn2+ (5 and 10 mM) had a stimulatory effect on xylanase activity. The biobleaching application showed that 30 U/g of xylanases during 15 min decreased Kappa number in 9.37. These results indicate SS as an alternative substrate for fungi fibrolytic enzymes production and the xylanase with low cellulase extract as a potential biobleaching application.