Enhancing Cellulase Production inAureobasidium pullulansby Genome Shuffling

Abstract

Cellulose is the most abundant renewable carbon source found in nature and is of great interest to various industries, including the food industry. Generally, microorganisms can be used to convert cellulosic materials into higher protein content, which can subsequently be used for animal feed. However, without the aid of cellulase, the cellulose structure is resistant to degradation. In this study, genome shuffling was used to improve cellulase production from Aureobasidium pullulans Y-2311-1. One strain developed via genome shuffling (A. pullulans GS23) displayed the largest increase in total cellulase activity on day one, which was a 6-fold increase compared to the wild-type strain. The A. pullulans GS23 strain also had an increase in exoglucanase and β-glucosidase activity compared to the wild-type strain (6.95-fold and 1.52-fold increase, respectively). The crude protein amount of A. pullulans GS23 had a 1.04-fold increase compared to the wild-type strain after 5 days of fermentation. As A. pullulans GS23 has increased cellulase production compared to the wild-type, this strain has the capability to develop improved, protein-rich animal feed by decreasing the amount of commercial enzymes used in the fermentation process. This is the first known attempt to increase cellulase with genome shuffling in A. pullulans.