Recent Advances of L-ornithine Biosynthesis in Metabolically Engineered Corynebacterium glutamicum

Bacillus amyloliquefaciens is the dominant strain used to produce γ-polyglutamic acid from inulin, a non-grain raw material. B. amyloliquefaciens has a highly efficient tricarboxylic acid cycle metabolic flux and glutamate synthesis ability. These features confer great potential for the synthesis of glutamate derivatives. However, it is challenging to efficiently convert high levels of glutamate to a particular glutamate derivative. Here, we conducted a systematic study on the biosynthesis of L-ornithine by B. amyloliquefaciens using inulin. First, the polyglutamate synthase gene pgsBCA of B. amyloliquefaciens NB was knocked out to hinder polyglutamate synthesis, resulting in the accumulation of intracellular glutamate and ATP. Second, a modular engineering strategy was applied to coordinate the degradation pathway, precursor competition pathway, and L-ornithine synthesis pathway to prompt high levels of intracellular precursor glutamate for l-ornithine synthesis. In addition, the high-efficiency L-ornithine transporter was further screened and overexpressed to reduce the feedback inhibition of L-ornithine on the synthesis pathway. Combining these strategies with further fermentation optimizations, we achieved a final L-ornithine titer of 31.3 g/L from inulin. Overall, these strategies hold great potential for strengthening microbial synthesis of high value-added products derived from glutamate.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Metabolic Engineering of Bacillus amyloliquefaciens to Efficiently Synthesize L-Ornithine From Inulin

Zhu

Hu²,

Yan³

et al. 2022

“…In this sense, special consideration should be paid to natural secondary metabolic routes conducting to NcAAs (or using them) to expand established MECs for their synthesis. Metabolic engineering of microorganisms have also allowed production of NcAAs such as L -norvaline/ L -norleucine ( Anderhuber et al, 2016 ), L -citruline ( Eberhardt et al, 2014 ), hydroxyproline ( Falcioni et al, 2015 ), L -ornithine ( Wu et al, 2020 ) different D -α-AAs ( Mutaguchi et al, 2018 ) or different N -Alkylated AAs ( Mindt et al, 2019 , 2020 ; van der Hoek et al, 2019 ). Thus, isolated enzymes comprised in biosynthetic metabolic routes for the production of different compounds ( Hedges and Ryan, 2020 ) might find application on some of the existing MECs described in this paper.…”

Section: Multienzymatic Cascades For the Production Of Ncaasmentioning

confidence: 99%

Overview on Multienzymatic Cascades for the Production of Non-canonical α-Amino Acids

Martínez‐Rodríguez

Torres

Sánchez

et al. 2020

The 22 genetically encoded amino acids (AAs) present in proteins (the 20 standard AAs together with selenocysteine and pyrrolysine), are commonly referred as proteinogenic AAs in the literature due to their appearance in ribosome-synthetized polypeptides. Beyond the borders of this key set of compounds, the rest of AAs are generally named imprecisely as non-proteinogenic AAs, even when they can also appear in polypeptide chains as a result of post-transductional machinery. Besides their importance as metabolites in life, many of D-α-and L-α-"non-canonical" amino acids (NcAAs) are of interest in the biotechnological and biomedical fields. They have found numerous applications in the discovery of new medicines and antibiotics, drug synthesis, cosmetic, and nutritional compounds, or in the improvement of protein and peptide pharmaceuticals. In addition to the numerous studies dealing with the asymmetric synthesis of NcAAs, many different enzymatic pathways have been reported in the literature allowing for the biosynthesis of NcAAs. Due to the huge heterogeneity of this group of molecules, this review is devoted to provide an overview on different established multienzymatic cascades for the production of non-canonical D-α-and L-α-AAs, supplying neophyte and experienced professionals in this field with different illustrative examples in the literature. Whereas the discovery of new or newly designed enzymes is of great interest, dusting off previous enzymatic methodologies by a "back and to the future" strategy might accelerate the implementation of new or improved multienzymatic cascades.

“…Since isolation in 1957, Corynebacterium glutamicum has been intensively applied for biobased chemical production due to its ability to secrete amino acids, which are traditionally used as drugs or health products (Kogure and Inui, 2018;Wu et al, 2019). These amino acids and their derived chemicals are worth billions of dollars per year.…”

Section: Introductionmentioning

confidence: 99%

Recent Progress on Chemical Production From Non-food Renewable Feedstocks Using Corynebacterium glutamicum

Zhang

Jiang

et al. 2020

Self Cite

Due to the non-renewable nature of fossil fuels, microbial fermentation is considered a sustainable approach for chemical production using glucose, xylose, menthol, and other complex carbon sources represented by lignocellulosic biomass. Among these, xylose, methanol, arabinose, glycerol, and other alternative feedstocks have been identified as superior non-food sustainable carbon substrates that can be effectively developed for microbe-based bioproduction. Corynebacterium glutamicum is a model gram-positive bacterium that has been extensively engineered to produce amino acids and other chemicals. Recently, in order to reduce production costs and avoid competition for human food, C. glutamicum has also been engineered to broaden its substrate spectrum. Strengthening endogenous metabolic pathways or assembling heterologous ones enables C. glutamicum to rapidly catabolize a multitude of carbon sources. This review summarizes recent progress in metabolic engineering of C. glutamicum toward a broad substrate spectrum and diverse chemical production. In particularly, utilization of lignocellulosic biomass-derived complex hybrid carbon source represents the futural direction for non-food renewable feedstocks was discussed.