Editorial: Biosynthesis of Amino Acids and Their Derived Chemicals From Renewable Feedstock (2025)

A new metabolic route for the fermentative production of 5-aminovalerate from glucose and alternative carbon sources

Bioresource Technology, 2017

Here, a new metabolic pathway for the production of 5-aminovalerate (5AVA) from L-lysine via cadaverine as intermediate was established and this three-step-pathway comprises Llysine decarboxylase (LdcC), putrescine transaminase (PatA) and γ-aminobutyraldehyde dehydrogenase (PatD). Since Corynebacterium glutamicum is used for industrial L-lysine production, the pathway was established in this bacterium. Upon expression of ldcC, patA and patD from Escherichia coli in C. glutamicum wild type, production 5AVA was achieved. Enzyme assays revealed that PatA and PatD also converted cadaverine to 5AVA. Eliminating the by-products cadaverine, N-acetylcadaverine and glutarate in a genome-streamlined Llysine producing strain expressing ldcC, patA and patD improved 5AVA production to a titer of 5.1 g L-1 , a yield of 0.13 g g-1 and a volumetric productivity of 0.12 g L-1 h-1. Moreover, 5AVA production from the alternative feedstocks starch, glucosamine, xylose and arabinose was established.

Production of Biopolyamide Precursors 5-Amino Valeric Acid and Putrescine From Rice Straw Hydrolysate by Engineered Corynebacterium glutamicum

Frontiers in Bioengineering and Biotechnology, 2021

The non-proteinogenic amino acid 5-amino valeric acid (5-AVA) and the diamine putrescine are potential building blocks in the bio-polyamide industry. The production of 5-AVA and putrescine using engineered Corynebacterium glutamicum by the co-consumption of biomass-derived sugars is an attractive strategy and an alternative to their petrochemical synthesis. In our previous work, 5-AVA production from pure xylose by C. glutamicum was shown by heterologously expressing xylA from Xanthomonas campestris and xylB from C. glutamicum. Apart from this AVA Xyl culture, the heterologous expression of xylAXc and xylBCg was also carried out in a putrescine producing C. glutamicum to engineer a PUT Xyl strain. Even though, the pure glucose (40 g L–1) gave the maximum product yield by both the strains, the utilization of varying combinations of pure xylose and glucose by AVA Xyl and PUT Xyl in CGXII synthetic medium was initially validated. A blend of 25 g L–1 of glucose and 15 g L–1 of xylose in...

Metabolic engineering of Corynebacterium glutamicum for enhanced production of 5-aminovaleric acid

Background: 5-Aminovaleric acid (5AVA) is an important five-carbon platform chemical that can be used for the synthesis of polymers and other chemicals of industrial interest. Enzymatic conversion of l-lysine to 5AVA has been achieved by employing lysine 2-monooxygenase encoded by the davB gene and 5-aminovaleramidase encoded by the davA gene. Additionally, a recombinant Escherichia coli strain expressing the davB and davA genes has been developed for bioconversion of l-lysine to 5AVA. To use glucose and xylose derived from lignocellulosic biomass as substrates, rather than l-lysine as a substrate, we previously examined direct fermentative production of 5AVA from glucose by metabolically engineered E. coli strains. However, the yield and productivity of 5AVA achieved by recom-binant E. coli strains remain very low. Thus, Corynebacterium glutamicum, a highly efficient l-lysine producing microorganism , should be useful in the development of direct fermentative production of 5AVA using l-lysine as a precursor for 5AVA. Here, we report the development of metabolically engineered C. glutamicum strains for enhanced fermenta-tive production of 5AVA from glucose. Results: Various expression vectors containing different promoters and origins of replication were examined for optimal expression of Pseudomonas putida davB and davA genes encoding lysine 2-monooxygenase and delta-aminovaleramidase, respectively. Among them, expression of the C. glutamicum codon-optimized davA gene fused with His 6-Tag at its N-Terminal and the davB gene as an operon under a strong synthetic H 36 promoter (plasmid p36davAB3) in C. glutamicum enabled the most efficient production of 5AVA. Flask culture and fed-batch culture of this strain produced 6.9 and 19.7 g/L (together with 11.9 g/L glutaric acid as major byproduct) of 5AVA, respectively. Homology modeling suggested that endogenous gamma-aminobutyrate aminotransferase encoded by the gabT gene might be responsible for the conversion of 5AVA to glutaric acid in recombinant C. glutamicum. Fed-batch culture of a C. glutamicum gabT mutant-harboring p36davAB3 produced 33.1 g/L 5AVA with much reduced (2.0 g/L) production of glutaric acid. Conclusions: Corynebacterium glutamicum was successfully engineered to produce 5AVA from glucose by optimizing the expression of two key enzymes, lysine 2-monooxygenase and delta-aminovaleramidase. In addition, production of glutaric acid, a major byproduct, was significantly reduced by employing C. glutamicum gabT mutant as a host

Biotechnological production of amino acids

For almost 50 years now, biotechnological production processes have been used for industrial production of amino acids. Market development has been particularly dynamic for the flavor-enhancer glutamate and the animal feed amino acids L-lysine, L-threonine, and L-tryptophan, which are produced by fermentation processes using highperformance strains of Corynebacterium glutamicum and Escherichia coli from sugar sources such as molasses, sucrose, or glucose. But the market for amino acids in synthesis is also becoming increasingly important, with annual growth rates of 5-7%. The use of enzymes and whole cell biocatalysts has proven particularly valuable in production of both proteinogenic and nonproteinogenic L-amino acids, D-amino acids, and enantiomerically pure amino acid derivatives, which are of great interest as building blocks for active ingredients that are applied as pharmaceuticals, cosmetics, and agricultural products. Nutrition and health will continue to be the driving forces for exploiting the potential of microorganisms, and possibly also of suitable plants, to arrive at even more efficient processes for amino acid production.

Metabolic engineering for 4-aminophenylalanine production from lignocellulosic biomass by recombinant <i>Escherichia coli</i>

2023

To synthesize a high-performance biopolyimide bioplastic from lignocellulosic feedstock, Escherichia coli was metabolically engineered to produce 4-amino-L-phenylalanine (4APhe) as a diamine monomer. A highbiomass sorghum cultivar was used as the model lignocellulosic feedstock, and the enzymatic hydrolysate was used as a substrate for 4APhe production in fed-batch culture. When using the ldh mutant strain, HKE6027, 4APhe production from glucose was increased by over threefold compared to the parent strain. This increase was due to the disruption of biosynthetic pathways that produce either acetate or lactate as by-products. Comparative metabolomic analysis revealed increased flux in both the pentose phosphate and shikimate pathways in HKE6027, resulting in the highest yields. However, 5.7 g L −1 of 4APhe was produced from enzymatic hydrolysis by HKE6027, which was 24% lower than that obtained from glucose. The concentrations of 14 potential fermentation inhibitors present in the enzymatic hydrolysate were determined, and their inhibitory effects on both cell growth and 4APhe production were examined. The addition of groups of potential inhibitors present in the enzymatic hydrolysate of sorghum bagasse showed that benzaldehyde-and cinnamic acid derivatives inhibited 4APhe fermentation at low concentrations (halfmaximum inhibitor concentration IC 50 = 16 mg L −1), whereas furfural and 5-hydroxymethylfurfural, which are well-known fermentation inhibitors, inhibited 4APhe fermentation at relatively high concentrations (IC 50 = 640 mg L −1). These results provide insight into the design of metabolic pathways tailored for the utilization of lignocellulosic biomass to produce aromatic compounds through the shikimate pathway. Sustainability spotlight This study produced a starting material for the synthesis of polyimide from an inedible and renewable feedstock of lignocellulosic biomass using microbial fermentation. This process can produce an organic molecule from plant biomass for CO 2 xation and convert it into a high-performance bioplastic, resulting in the long-term mitigation of greenhouse gas emissions in the industrial sector. Therefore, this study contributes to the circular economy and alternative plastic raw material production for a sustainable society. Furthermore, this work aligns with goals 12 of "Responsible Consumption and Production" and 13 of "Climate Action" of the United Nation's Sustainable Development Goals.

Fermentative Production of N-Alkylated Glycine Derivatives by Recombinant Corynebacterium glutamicum Using a Mutant of Imine Reductase DpkA From Pseudomonas putida

Frontiers in Bioengineering and Biotechnology

Accelerated pentose utilization by Corynebacterium glutamicum for accelerated production of lysine, glutamate, ornithine and putrescine

Microbial Biotechnology, 2013

Because of their abundance in hemicellulosic wastes arabinose and xylose are an interesting source of carbon for biotechnological production processes. Previous studies have engineered several Corynebacterium glutamicum strains for the utilization of arabinose and xylose, however, with inefficient xylose utilization capabilities. To improve xylose utilization, different xylose isomerase genes were tested in C. glutamicum. The gene originating from Xanthomonas campestris was shown to have the highest effect, resulting in growth rates of 0.14 h -1 , followed by genes from Bacillus subtilis, Mycobacterium smegmatis and Escherichia coli. To further increase xylose utilization different xylulokinase genes were expressed combined with X. campestris xylose isomerase gene. All combinations further increased growth rates of the recombinant strains up to 0.20 h -1 and moreover increased biomass yields. The gene combination of X. campestris xylose isomerase and C. glutamicum xylulokinase was the fastest growing on xylose and compared with the previously described strain solely expressing E. coli xylose isomerase gene delivered a doubled growth rate. Productivity of the amino acids glutamate, lysine and ornithine, as well as the diamine putrescine was increased as well as final titres except for lysine where titres remained unchanged. Also productivity in medium containing rice straw hydrolysate as carbon source was increased.

Systems metabolic engineering of Corynebacterium glutamicum and Bacillus methanolicus for production of new products from alternative carbon sources

2018

Background: The steadily growing world population and our ever luxurious life style, along with the simultaneously decreasing fossil resources has confronted modern society with the issue and need of finding renewable routes to accommodate for our demands. Shifting the production pipeline from raw oil to biomass requires efficient processes for numerous platform chemicals being produced with high yield, high titer and high productivity. Results: In the present work, we established a de novo bio-based production process for the two carbon-5 platform chemicals 5-aminovalerate and glutarate on basis of the lysine-hyperproducing strain Corynebacterium glutamicum LYS-12. Upon heterologous implementation of the Pseudomonas putida genes davA, encoding 5-aminovaleramidase and davB, encoding lysine monooxygenase, 5-aminovalerate production was established. Related to the presence of endogenous genes coding for 5-aminovalerate transaminase (gabT) and glutarate semialdehyde dehydrogenase, 5-aminovalerate was partially converted to glutarate. Moreover, residual l-lysine was secreted as by-product. The issue of by-product formation was then addressed by deletion of the lysE gene, encoding the l-lysine exporter. Additionally, a putative gabT gene was deleted to enhance 5-aminovalerate production. To fully exploit the performance of the optimized strain, fed-batch fermentation was carried out producing 28 g L −1 5-aminovalerate with a maximal spacetime yield of 0.9 g L −1 h −1. Conclusions: The present study describes the construction of a recombinant microbial cell factory for the production of carbon-5 platform chemicals. Beyond a basic proof-of-concept, we were able to specifically increase the production flux of 5-aminovalerate thereby generating a strain with excellent production performance. Additional improvement can be expected by removal of remaining by-product formation and bottlenecks, associated to the terminal pathway, to generate a strain being applicable as centerpiece for a bio-based production of 5-aminovalerate.

Metabolic engineering of Escherichia coli and Corynebacterium glutamicum for biotechnological production of organic acids and amino acids

Current Opinion in Microbiology, 2006

Industrial microorganisms have been developed as biocatalysts to provide new or to optimize existing processes for the biotechnological production of chemicals from renewable plant biomass. Rational strain development by metabolic engineering is crucial to successful processes, and is based on efficient genetic tools and detailed knowledge of metabolic pathways and their regulation. This review summarizes recent advances in metabolic engineering of the industrial model bacteria Escherichia coli and Corynebacterium glutamicum that led to efficient recombinant biocatalysts for the production of acetate, pyruvate, ethanol, D-and L-lactate, succinate, L-lysine and L-serine.

Efficient cell factories for the production of N‐methylated amino acids and for methanol‐based amino acid production

Microbial Biotechnology

SummaryThe growing world needs commodity amino acids such as L‐glutamate and L‐lysine for use as food and feed, and specialty amino acids for dedicated applications. To meet the supply a paradigm shift regarding their production is required. On the one hand, the use of sustainable and cheap raw materials is necessary to sustain low production cost and decrease detrimental effects of sugar‐based feedstock on soil health and food security caused by competing uses of crops in the feed and food industries. On the other hand, the biotechnological methods to produce functionalized amino acids need to be developed further, and titres enhanced to become competitive with chemical synthesis methods. In the current review, we present successful strain mutagenesis and rational metabolic engineering examples leading to the construction of recombinant bacterial strains for the production of amino acids such as L‐glutamate, L‐lysine, L‐threonine and their derivatives from methanol as sole carbon s...