Biotechnological production and statistical optimization of fungal xylanase by bioconversion of the lignocellulosic biomass residues in solid-state fermentation

Most of the lignocellulosic biomass residues are decomposed and transformed by a variety of microbes in the natural environment. The xylanase production from Aspergillus niger strain BG has been produced using wheat bran under solid-state fermentation (SSF). One factor at a time approach (OFAT) was used to optimize the effect of the incubation period, initial pH, moisture content, and cultivation temperature on the xylanase production. Furthermore, experiments were designed with a Box–Behnken design (BBD) on the same variables using response surface methodology (RSM). Analysis of variance (ANOVA) was carried out and the xylanase production was expressed with a mathematical equation depending on the factors. Maximum xylanase yield after OFAT approach and RSM optimization was significant with maximum values of 4008.25 ± 3.73 U/g of dry substrate (U/gds) and 5427.51 ± 4.4 U/gds which have been recorded respectively compared with the initial conditions (1899.02 ± 1.6 U/gds) after 7 days of fermentation. The effects of individual, interaction, and square terms on xylanase production were represented using the non-linear regression equations with significant R 2 and p values. The optimum conditions established by RSM method for the maximum xylanase production were obtained with a pH media of 2.5 at 37 °C using wheat bran as 84% humidified substrate after 66 h of incubation, this conditions resulted in 65.01% increased level of the xylanase production than produced in the initial conditions. Xylanase production from Aspergillus niger strain BG using RSM is considered advantageous for bioconversion of the agriculture residues. Graphical abstract