Bioconversion of Non-Detoxified Hemicellulose Hydrolysates to Xylitol by Halotolerant Yeast Debaryomyces nepalensis NCYC 3413
Bhaskar Paidimuddala and Sathyanarayana N Gummadi*
Applied and Industrial Microbiology Laboratory, Department of Biotechnology, IIT Madras, Chennai, India
- *Corresponding Author:
- Sathyanarayana N Gummadi
Professor, Applied and Industrial Microbiology Laboratory
Department of Biotechnology
Bhupat and Jyoti Mehta School of Biosciences
Indian Institute of Technology Madras, Chennai 600 036, India
E-mail: [email protected]
Received date: June 23, 2014; Accepted date: July 28, 2014; Published date: August 04, 2014
Citation: Paidimuddala B, Gummadi SN (2014) Bioconversion of Non-Detoxified Hemicellulose Hydrolysates to Xylitol by Halotolerant Yeast Debaryomyces nepalensis NCYC 3413. J Microb Biochem Technol 6:327-333. doi: 10.4172/1948-5948.1000163
Copyright: © 2014 Finore I, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Lignocellulosic materials are one of the most abundant renewable resources whose exploitation for the production of biochemicals and biofuels is the major challenge in the area of industrial biotechnology due to inhibition of growth and product formation by the toxic compounds released upon their hydrolysis. Indeed the bioprocess that can produce industrial products from hemicellulose hydrolysates in the presence of toxic compounds is economical than the process which involves detoxification. In this study, the ability of halotolerant strain Debaryomyces nepalensis NCYC 3413 to convert non-detoxified xylose enriched hemicellulose hydrolysates from corn cobs, rice straw, sugarcane bagasse and wheat straw to xylitol was evaluated. It was found that this strain has the capability to grow in all hemicellulose hydrolysates and convert xylose to xylitol without detoxification of hydrolysates. The maximum xylitol concentration of 14.6 g L-1 was obtained from corn cobs and wheat straw with productivities of 0.16 and 0.20 g L-1 h-1 respectively at a yield of 0.30 g g-1. Whereas sugarcane bagasse and rice straw gave xylitol yields of 0.31 and 0.32 g g-1 respectively with 14.2 g L-1 maximum xylitol and productivities were calculated to be 0.20 and 0.15 g L-1 h-1 respectively. The presence of high glucose hindered xylitol production by producing ethanol. Based on our findings, we suggest that (i) D. nepalensis is a promising strain for ecofriendly xylitol production as it exhibits broad specificity to lignocellulose substrates, fermentation of mixed sugars and (ii) tolerance towards lignocellulosic inhibitors making the process more economical.