A genome-based approach to create a minimally mutated Corynebacterium glutamicum strain for efficient l-lysine production

Abstract

Based on the progress in genomics, we have developed a novel approach that employs genomic information to generate an efficient amino acid producer. A comparative genomic analysis of an industrial L-lysine producer with its natural ancestor identified a variety of mutations in genes associated with L-lysine biosynthesis. Among these mutations, we identified two mutations in the relevant terminal pathways as key mutations for L-lysine production, and three mutations in central metabolism that resulted in increased titers. These five mutations when assembled in the wild-type genome led to a significant increase in both the rate of production and final L-lysine titer.Further investigations incorporated with transcriptome analysis suggested that other as yet unidentified mutations are necessary to support the L-lysine titers observed by the original production strain. Here we describe the essence of our approach for strain reconstruction, and also discuss mechanisms of L-lysine hyperproduction unraveled by combining genomics with classical strain improvement.

Characterization of mutations induced by N-methyl-N′-nitro-N-nitrosoguanidine in an industrial Corynebacterium glutamicum strain

“…Among the 34 missense mutations, four specific mutations, hom59 (a T to C exchange at position 176, leading to V59A), lysC311 (a C to T exchange at position 932, leading to T311I), pyc458 (a C to T exchange at position 1372, leading to P458S), and gnd361 (a C to T exchange at position 1083, leading to S361F), were defined as useful mutations relevant to L-lysine production, as described previously [6,7,21]. One nonsense mutation, mqo224 (a G to A exchange at position 672, leading to W224opal), was also a useful mutation for improved L-lysine production [21,22].…”

“…One nonsense mutation, mqo224 (a G to A exchange at position 672, leading to W224opal), was also a useful mutation for improved L-lysine production [21,22]. Some of these useful mutations were characterized for their phenotypic consequences, which were given in the legend of Table 2.…”

“…Our laboratories have recently determined the whole genome sequence of the wild-type strain of C. glutamicum, ATCC 13032 [19]. Following this, we analyzed mutations introduced at specific locations in the genome of a C. glutamicum L-lysine producer derived through multiple rounds of NTG mutagenesis, followed by reconstruction of the producer by assembling only beneficial mutations in a wild-type background [6,20,21]. In this process, we have identified numerous mutations accumulated in the producer's genome as reported previously [6,7,22,23].…”

Regulation and Intensification Ways of Lysine Biosynthesis

“…Потреби сільського гос-подарства, хар÷ової проìисловості та ìедиöини зуìовлюють інтенсивний розвиток проìислового виробниöтва лізину [2,3] [2,[5][6][7].…”

“…Óсі гени корі-небактерій, що кодують öі ферìенти, ізольовано та секвеновано [6,7,8,17]. Для кожного гена визна÷ені його ìісöе і функöія у ìетаболі÷ноìу шляху та у÷асть у транспортуванні лізину [10,11,12] [13][14][15][16] .…”