Metabolic regulation and overproduction of primary metabolites

Abstract

SummaryOverproduction of microbial metabolites is related to developmental phases of microorganisms. Inducers, effectors, inhibitors and various signal molecules play a role in different types of overproduction. Biosynthesis of enzymes catalysing metabolic reactions in microbial cells is controlled by well‐known positive and negative mechanisms, e.g. induction, nutritional regulation (carbon or nitrogen source regulation), feedback regulation, etc. The microbial production of primary metabolites contributes significantly to the quality of life. Fermentative production of these compounds is still an important goal of modern biotechnology. Through fermentation, microorganisms growing on inexpensive carbon and nitrogen sources produce valuable products such as amino acids, nucleotides, organic acids and vitamins which can be added to food to enhance its flavour, or increase its nutritive values. The contribution of microorganisms goes well beyond the food and health industries with the renewed interest in solvent fermentations. Microorganisms have the potential to provide many petroleum‐derived products as well as the ethanol necessary for liquid fuel. Additional applications of primary metabolites lie in their impact as precursors of many pharmaceutical compounds. The roles of primary metabolites and the microbes which produce them will certainly increase in importance as time goes on. In the early years of fermentation processes, development of producing strains initially depended on classical strain breeding involving repeated random mutations, each followed by screening or selection. More recently, methods of molecular genetics have been used for the overproduction of primary metabolic products. The development of modern tools of molecular biology enabled more rational approaches for strain improvement. Techniques of transcriptome, proteome and metabolome analysis, as well as metabolic flux analysis. have recently been introduced in order to identify new and important target genes and to quantify metabolic activities necessary for further strain improvement.

Production and Quality Analysis of Wine from Honey and Coconut Milk Blend Using Saccharomyces cerevisiae

“…This supported the opinion of the authors of this study that caloric and alcoholic contents are possible winery model indicators with assumed precision of 96% (p = 0.04) and 98% (p = 0.02), respectively. However, bioethanol quantity and quality depend mainly on the primary metabolites and microbial consortium of the system [26]. Apart from nutritional factors, technologies of fermentation, enzyme and metabolic engineering were necessary to optimize ethanol yield [27].…”

Investigation into the role of catabolite control protein A in the metabolic regulation of Streptococcus suis serotype 2 using gene expression profile analysis

“…CCR is a physiological phenomenon in which microorganisms use quick-impact carbon sources, such as glucose among mixed carbon sources, in the process of fermentation. Catabolite control protein A (CcpA) is a key regulator of pleiotropic functions in the process of CCR (5). Furthermore, CcpA is involved in numerous physiological processes, including the regulation of central carbon and nitrogen metabolism, biofilm formation and the expression of virulent genes.…”

Analysis and Manipulation of Aspartate Pathway Genes for l -Lysine Overproduction from Methanol by Bacillus methanolicus

“…Overexpression of wild-type and mutant aspartate pathway genes demonstrated that all six genes are important for L-lysine overproduction as tested in shake flasks, and the effects were dependent on the genetic background tested. Coupled overexpression of up to three genes resulted in additive (above 80-fold) increased L-lysine production levels.The essential amino acid L-lysine is widely used as a feed additive in animal farming, and currently Ͼ1,000,000 tons of L-lysine-HCl per year are produced worldwide by fermentation processes, using classical mutant strains of Corynebacterium glutamicum and its relatives (1,7,34). L-Lysine is a product of the aspartate pathway (Fig.…”

“…The essential amino acid L-lysine is widely used as a feed additive in animal farming, and currently Ͼ1,000,000 tons of L-lysine-HCl per year are produced worldwide by fermentation processes, using classical mutant strains of Corynebacterium glutamicum and its relatives (1,7,34). L-Lysine is a product of the aspartate pathway ( Fig.…”