Conclusive selection of optimal parameters for cellulase production by Talaromyces verruculosus IIPC 324 under SSF via saccharification of acid-pretreated sugarcane bagasse

ABSTRACT

Cellulase production studies were conducted with Talaromyces verruculosus IIPC 324 under solid state fermentation (SSF), and optimal parameters were conclusively selected via saccharification of acid-pretreated sugarcane bagasse. Various physicochemical parameters affecting cellulase production under SSF were optimized. Endoglucanase and cellobiase production responded differently under individual growth conditions. Maximum endoglucanase and cellobiase activity of ≥ 250 U/g and ≥ 45 U/g respectively was obtained when the strain was grown at 24°C for 4 days with an initial moisture content of 62.5% on wheat bran supplemented with 1.62% ammonium chloride. The enzyme cocktail obtained from these optimized growth conditions yielded 8.37 ± 0.75 g L⁻¹ reducing sugar from acid-pretreated sugarcane bagasse after 72 h at 60°C and pH 4.0. With the addition of Avicel PH-101 at 5% concentration in wheat bran, the cellulase cocktail of Talaromyces verruculosus IIPC 324 released 9.17 ± 0.60 g L⁻¹ and 7.82 ± 0.06 g L⁻¹ of total reducing sugars and glucose respectively at 60°C (pH 4.0) after 72 h. The addition of glucose and other simple sugars did not repress the cellulase production under SSF conditions, making Talaromyces verruculosus IIPC 324 an attractive candidate for cellulase production and its application for biofuel production from lignocellulosic biomass.

KEYWORDS:

• Solid state fermentation (SSF)
• Talaromyces verruculosus IIPC 324
• enzymatic saccharification
• carboxymethyl cellulase (CMCase)
• Reducing Sugars (RS)

Acknowledgements

The authors are grateful to Director Dr. Anjan Ray, CSIR – Indian Institute of Petroleum, for constant encouragement and for providing necessary facilities to complete this work. This research was funded by CSIR-IIP as an in-house project under OLP-350919. We would like to thank Dr. Debashish Ghosh, Scientist Biofuel Division, for kindly providing acid-pretreated sugarcane bagasse for the entire study. The senior research fellowship awarded to Ms. Lavika Jain by the Council of Scientific and Industrial Research, New Delhi, India, is greatly acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was funded by CSIR-Indian Institute of Petroleum as an in-house project [grant number OLP- 350 919].