Evaluation of endoglucanase and xylanase production by Aspergillus tamarii cultivated in agro-industrial lignocellulosic biomasses.

Abstract

To better understand the production of enzymes of industrial interest from microorganisms with biotechnological potential using lignocellulosic biomass, we evaluated the production of endoglucanase and xylanase from Aspergillus tamarii. CAZymes domains were evaluated in the genome, and a screening of the enzymatic potential of A. tamarii in various agricultural biomasses was done. The enzymatic profile could be associated with the biomass complexity, with increased biomass recalcitrance yielding higher activity. A time-course profile defined 48h of cultivation as the best period for cultivating A. tamarii in sugarcane bagasse reached 12.05IU/mg for endoglucanase and 74.86IU/mg for xylanase. Using 0.1% (w/v) tryptone as the only nitrogen source and 12µmol/L CuSO4 addition had an overall positive effect on the enzymatic activity and protein production. A 22 factorial central composite design was used then to investigate the simultaneous influence of tryptone and CuSO4 on enzyme activity. Tryptone strongly affected enzymatic activity, decreasing endoglucanase activity but increasing xylanase activity. CuSO4 supplementation was advantageous for endoglucanases, increasing their activity, and it had a negative effect on xylanases. But overall, the experimental design increased the enzymatic activity of all biomasses used. For the clean cotton residue, the experimental design was able to reach the highest enzyme activity for endoglucanase and xylanase, with 1.195IU/mL and 6.353IU/mL, respectively. More experimental studies are required to investigate how the biomass induction effect impacts enzyme production.