The amino acids are building blocks of protein molecules and hence used in dietary and feed supplements of human and animals, respectively (Mahmood 2015). These organic molecules have various role, such as animal feed additives (lysine, methionine, threonine), flavor enhancers (aspartic acid, monosodium glutamate, serine), antioxidants (cysteine, L-tryptophan and L-histidine), as sweeteners (aspartame made from aspartic acid and phenylalanine), and ingredients in cosmetic and medicinal products (Bommarius et al. 1998; Ikeda 2003; Mueller and Huebner2003;Leuchtenberger et al. 2005; Park and Lee 2008; Ivanov et al. 2014).
Additionally, amino acids are suggested as dietary supplements for body building, bruxism, depression, sleep aid, premenstrual dysphoric disorder, attention deficit-hyperactivity disorder, and smoking cessation. Nonessential amino acids can be synthesized by human body but essential amino acids cannot be synthesized in human body but are required for protein synthesis and therefore, dietary supplement is necessary from external sources.
Hence, production of essential amino acids at industrial scale using microbial sources is promising and desirable. The worldwide production technology for amino acids is dominated by microbial fermentation and enzymatic processes owing to cost-effectiveness, ecological acceptability and ease to produce enantiomerically pure amino acids