Improved biobleaching of mixed hardwood pulp and process optimization using novel GA-ANN and GA-ANFIS hybrid statistical tools

Abstract

The process parameters for xylanase biobleaching of mixed hardwood pulp like, reaction time (6-35 h), pulp consistency (2.5-15%) and xylanase dose (5-35 U) were optimized using OFAT approach and hybrid statistical tools viz. GA-ANN and GA-ANFIS. The biobleaching ability of xylanase in terms of reducing sugar yield increased up to 28.16 mg g^-1 (28.05%) than OFAT optimization (21.99 mg g^-1 of pulp) after employing hybrid statistical tools. After TCF bleaching of xylanase treated pulp, we observed that lignin content reduced to 0.29% whereas it was still 0.41% in the untreated pulp. Moreover, the brightness level achieved up to 70.4% in xylanase treated pulp while it was only 53.60% in the chemically treated pulp. The kappa number for xylanase treated, chemically treated, and xylanase-chemical treated pulp was recorded 9.90, 7.10 and 4.70, respectively. The present study reports an improved eco-friendly biobleaching method using novel GA-ANN and GA-ANFIS hybrid statistical tools.

Keywords: Biobleaching; Hybrid statistical tools; Paper and pulp; Thermomyces lanuginosus; Xylanase.