Amino Acids

Since discovery of Corynebacterium glutamicum in 1956, amino acid production by microbial fermentation is one of most successful biotechnology models in a sustainable bioeconomy. Amino acid market is growing steadily by gradual increase of commodity, l-glutamate, l-lysine, and methionine, as well as rapid expansion of specialty amino acids, such as branched amino acids, l-arginine, and l-cysteine. Currently, most amino acids are produced by microbial fermentation, while sulfur-containing l-methionine and l-cysteine are commercialized by combined technology of fermentation of precursor and enzyme catalysis. With the advent of genomics and functional genomics in the 2000s, creation of genetically defined C. glutamicum and Escherichia coli that produce l-lysine and l-threonine, respectively, is considered a remarkable milestone and breakthrough in strain engineering for industrial production of several amino acids. Systems metabolic engineering for superior amino acid-producing strains is supported by novel functional tools that provide simplicity, efficiency, and high-throughput as well as by individual engineering strategies that provide high titer, yield, productivity, and sustainability. This chapter outlines recent functional tools and important engineering strategies for amino acid production. Moreover, it covers the recent advances in systems metabolic engineering for amino acids production, including l-glutamate, l-arginine, l-lysine, l-methionine, l-cysteine, and l-histidine. Myriad efforts to develop novel engineering tools and strategies are expected to dramatically increase the production performance of amino acid producers and accelerate the expansion of product portfolios such as amino acid derivatives and other value-added compounds.