Utilization of pretreated bagasse for the sustainable bioproduction of cellulase by Aspergillus nidulans MTCC344 using response surface methodology

• Published in: Industrial crops and products Vol. 34; no. 3; pp. 1564 - 1571
• Main Authors: Anuradha Jabasingh, S., Valli Nachiyar, C.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2011
• Subjects: Aspergillus nidulans MTCC344; Central composite design; CMCase; Pretreated bagasse; Response surface methodology; Solid state fermentation; Central composite design; CMCase; Response surface methodology; Aspergillus nidulans MTCC344; Pretreated bagasse; Solid state fermentation
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2011.05.017

► Response surface methodology (RSM) employing a four- factor- five - level central composite design used to optimize the conditions for the production of endo β-1, 4 glucanase, a component of cellulase by Aspergillus nidulans MTCC344 under bagasse solid state fermentation provided maximum cellulase activity of 28.96 Ug −1 at the optimum conditions, 16.8 mm bagasse bed height, 60% moisture content, pH 4.25 and temperature 40 °C in the solid state fermenter. ► Complete hydrolysis of sodium hydroxide pretreated bagasse by Aspergillus nidulans MTCC344 was observed after 8 days of incubation with significant endo β-1, 4 glucanase activities. Structural changes were observed through pretreatment, in favor of enzymatic hydrolysis as revealed by the results of Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) of bagasse. ► The techniques adopted including response surface methodology, solid state fermentation and alkali pretreatment facilitated in fabricating cellulase of desired activity in shorter period, aided in reducing the cost of cellulase production and consequently afforded an innovative solution to the need of reusing one of the few dumped waste ‘the bagasse’. Response surface methodology (RSM) was used to optimize the conditions for the production of endo β-1,4 glucanase, a component of cellulase by Aspergillus nidulans MTCC344 under solid state fermentation, using bagasse as the chief substrate. A four-factor-five-level central composite design was employed for experimental design and analysis of the results. Maximum cellulase activity (CMCase was 28.96 U g −1) can be attained at the optimum conditions, 16.8 mm bagasse bed height, 60% moisture content, pH 4.25 and temperature 40 °C in the solid state fermenter. These data were rather close to the experimental results obtained (CMCase was 28.84 U g −1). A. nidulans MTCC344 was able to hydrolyze pretreated bagasse completely after 8 days of incubation with significant endo β-1,4 glucanase activities. The results of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) of bagasse showed structural changes through pretreatment, in favor of enzymatic hydrolysis. Bagasse with alkali pretreatment using sodium hydroxide is a source of lignocelluloses able to improve the yield of endo β-1,4 glucanase by the strain of A. nidulans. The endo β-1,4 glucanase produced during the bioconversion of cellulose to glucose by A. nidulans MTCC344 is strongly dependent on the pretreatment given before hydrolysis.