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

Keerthi Sasikumar,K Madhavan Nampoothiri,Volker F Wendisch,Silvin Hannibal

doi:10.3389/fbioe.2021.635509

Abstract

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 CGXII medium yielded 109 ± 2 mg L–1 putrescine and 874 ± 1 mg L–1 5-AVA after 72 h of fermentation. Subsequently, to demonstrate the utilization of biomass-derived sugars, the alkali (NaOH) pretreated-enzyme hydrolyzed rice straw containing a mixture of glucose (23.7 g L–1) and xylose (13.6 g L–1) was fermented by PUT Xyl and AVA Xyl to yield 91 ± 3 mg L–1 putrescine and 260 ± 2 mg L–1 5-AVA, respectively, after 72 h of fermentation. To the best of our knowledge, this is the first proof of concept report on the production of 5-AVA and putrescine using rice straw hydrolysate (RSH) as the raw material.

Highlights

The severe global environmental impact of the polyamide industries demands an alternative process to their current synthesis from the petrochemical routes
A global high-performance polyamide market size report (Grand View Research Inc, 2020) projects a Compound annual growth rate (CAGR) of 7.1% for the high-performance polyamides from 2020 to 2027 as their consumption is highly increased for the production of insulation materials, industrial brushes and medical, healthcare products. 5-amino valeric acid (5-AVA) is naturally produced as an intermediate by Pseudomonas putida in the degradation of L-lysine by AMV pathway (Liu et al, 2014), whereas, in Pseudomonas aeruginosa 5-AVA is produced by the transamination and oxidation of cadaverine, which in turn is produced by the decarboxylation of lysine (Jae et al, 2013)
A detailed study was conducted with varying concentrations of glucose (5–40 g L−1) and xylose (5–40 g L−1), to analyze the efficacy of both AVA Xyl and PUT Xyl strains in co-utilizing pure glucose and xylose initially making a total sugar of 40 g L−1 in CGXII minimal medium

Summary

Introduction

The severe global environmental impact of the polyamide industries demands an alternative process to their current synthesis from the petrochemical routes. Apart from considering the importance of this five-carbon non-proteinogenic amino acid, as a potential monomer for the synthesis of nylon 5 and nylon 65 (Pukin et al, 2010; Adkins et al, 2013), their biotechnological production gains considerable interest. Successful metabolic engineering approaches have been established in E. coli and Corynebacterium strains for the production of 5-AVA from glucose, by the expression of L-lysine monoxygenase (DavB) and 5-amino valeramide amidohydrolase (DavA) genes of Pseudomonas putida (Cho et al, 2016). Schneider et al (2012) have reported a stable putrescine production from glucose with C. glutamicum by modifying the OTC activity and by expressing ornithine decarboxylase gene speC from E. coli

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