COMPARATIVE STUDY OF GLUTAMIC ACID PRODUCTION BY WILD-TYPE AND MUTANT STRAINS OF CORYNEBACTERIUM GLUTAMICUM

COMPARATIVE STUDY OF GLUTAMIC ACID PRODUCTION BY WILD-TYPE AND MUTANT STRAINS OF CORYNEBACTERIUM GLUTAMICUM

CHAPTER ONE

INTRODUCTION

Corynebacterium glutamicum is a rod-shaped Gram-positive aerobic bacterium, which can be found in soil, sewages, vegetables, and fruits (Eggeling and Bott, 2005). This bacterium is capable of utilizing various sugars as well as organic acids (Blombach and Seibold, 2010). Among others, C. glutamicum has the ability to metabolize glucose, fructose, and sucrose as well as lactate, pyruvate, and acetate (Blombach and Seibold, 2010); additionally, C. glutamicum has the ability to grow on mixtures of different carbon sources with a monoauxic growth (Wendisch et al., 2000) as opposed to diauxic growth observed for many other microorganisms such as Escherichia coli and Bacillus subtilis. Only a few exceptions have been reported as in the case of glucose-ethanol or acetate-ethanol mixtures, where preferential substrate utilization was observed (Zahoor et al., 2012). Since its discovery, C. glutamicum has become an indispensable microorganism for the biotechnological industry (Wendisch, 2014). With the development of amino acid market, a new era for the production of these amino acids by many companies and academic associations have enthusiastically arisen with the start of research and development in this field to increase the rate of amino acid production. This technological race has expedited the expansion of amino acid production by various methods. Thus, almost all the amino acids can be produced by any of the four methods which include; chemical synthesis, protein hydrolysis, enzymatic synthesis and fermentation. However, industrially, the most advantageous and economical method used for amino acids manufacture is microbial.