Int. J. Bioinformatics and Biological Sci.: v.2 n.1&2, p. 71-83. March and June 2014

optimization of fermentation Parameters for R3DSc5

and R3DPmP Strains for Ethanol Production

Sanjeeva Rao Durbha, mohan Dev tawa, girijashankar guntuku,

Prabhakar tadimalla,venkateswara Rao yechuri and

venkata Subba Rao muktinutalapati.

Department of Botany, Andhra University, India.

*Pharmaceutical Biotechnology Division,

A. U. College of Pharmaceutical Sciences, India.

* Corresponding author: Sanjeeva Rao Durbha; sraodurbha@gmail.com

abstract

Two newly isolated strains of Saccharomyces cerevisiae - R3DPMP and R3DSC5

were subjected to optimization studies with varying inoculum size, initial glucose

concentration, initial pH and temperature using yeast extract peptone dextrose

medium. Both the strains accumulated peak ethanol early with higher inoculum

density and exhibited similar pattern with changing initial pH. Though higher

glucose tolerance was noticed, 20% g/v and 25% g/v glucose concentration were

found to be optimum for R3DPMP and R3DSC5 respectively. Similar amount of

ethanol was accumulated within 30-40 0 C temperature by R3DPMP and 30-35 0 C

temperature by R3DSC5. However, based on higher temperature tolerance, sugar

tolerance and peak ethanol level, R3DSC5 appears to be superior to R3DPMP.

Therefore, R3DPMP strain is recommended for brewery industry whereas R3DSC5

for both brewery and very high gravity fermentation.

Keywords: Saccharomyces cerevisiae, ethanol, tolerance, Very High Gravity

fermentation.

Biofuel research gained huge importance due to the projected rapid decrease in

fossil fuel reserves because of increased global demand (Campbell and Laherrere,

1998). Use of ethanol as fuel is expected to reduce climatic change and global

warming (Sheehan and Himmel, 1999) by bringing about 86% reduction in

greenhouse gas emissions (Wang, 2005) and increased interest to develop rural

economies by establishing agro-dependent industries (Oscar and Carlos, 2008).

Bioethanol is produced by the fermentation of sugars by microorganisms such as

Saccharomyces cerevisiae, Zymomonas mobilis (Gi-Wook et al., 2008) , Mucor

indicus (Anna et al., 2005), thermophillic bacteria like Clostridium thermocellum

and C. thermohydrosulfuricum (Lovitt et al., 1984), filamentous fungi- Monilia