Xylanase production using agro-residue in solid-state fermentation from Bacillus pumilus ASH for biodelignification of wheat straw pulp

Abstract

Two stage statistical design was used to optimize xylanase production from Bacillus pumilus ASH under solid-state fermentation. Initially, Plackett-Burman designing (PB) was used for the selection of crucial production parameters. Peptone, yeast extract, incubation time, moisture level and pH were found to be the crucial factors for the xylanase production. Crucial variables were further processed through central composite designing (CCD) of response surface methodology (RSM) to maximize the xylanase yield. Each significant factor was investigated at five different levels to study their influence on enzyme production. Statistical approach resulted in 2.19-fold increase in xylanase yield over conventional strategy. The determination coefficient (R (2)) as shown by analysis of variance (ANOVA) was 0.9992, which shows the adequate credibility of the model. Potential of cellulase-free xylanase was further investigated for biobleaching of wheat straw pulp. Xylanase aided bleaching through XCDED(1)D(2) sequence resulted in 20 and 17% reduction in chlorine and chlorine dioxide consumption as compared to control. Significant increase in pulp brightness (%ISO), whiteness and improvement in various pulp properties was also observed.

Biobleaching application of cellulase poor and alkali stable xylanase from Bacillus pumilus SV-85S

“…The release of reducing sugars was statistically non-significant at different pH values. The optimum working efficiency of xylanase used in this study at pH 9.0 was in accordance with earlier reports (Garg et al 2011; Kaur et al 2011). However, the majority of cited work documented the optimum pH in the range of 6.0–8.0 (Chandralata et al 2004; Sanghi et al 2008; Manimaran et al 2009; Ko et al 2011).…”

“…Though statistically at par with 7.5 IU, 10 IU/gds has been selected as the optimum enzyme dose for further experiments because of the lowest mean Kappa number and highest brightness at this dose. An enzyme dose of 10 IU/g pulp was found to be optimum for biobleaching of mixed hardwood kraft pulp by several researchers (Sindhu et al 2006; Ahlawat et al 2007; Dhiman et al 2009; Sanghi et al 2009; Garg et al 2011). In contrast, maximum bleaching was reported with enzyme dose more than 10 IU/g (Kulkarni and Rao 1996; Bissoon et al 2002; Khandeparkar and Bhosle 2007).…”

“…Since Kappa number was the lowest at 55 °C, this temperature was used for further experiments. Several researchers have reported optimum temperature in the range of 50–60 °C for pulp biobleaching (Beg et al 2000; Sindhu et al 2006; Battan et al 2007; Dhiman et al 2009; Garg et al 2011). …”

“…Several researchers have reported an increase in brightness and decline in Kappa number but with variable magnitude following the xylanase pretreatment (Jiang et al 2006; Ahlawat et al 2007; Sanghi et al 2008; Garg et al 2011). The increase in brightness after enzyme pretreatment might be due two reasons.…”

Glucoamylase production from food waste by solid state fermentation and its evaluation in the hydrolysis of domestic food waste

“…Initial pH (X1), moisture content (X2, %, w/w), inoculum loading (X3, inoculum/g substrate) and time (X4, day) were chosen as independent input variables as they are the most important parameters for enzyme production during SSF (Garg et al, 2011). The GA activity (Units/gram dry solid or U/gds) was used as dependent output variables.…”