A novel biocatalyst for efficient production of 2-oxo-carboxylates using glycerol as the cost-effective carbon source

Abstract

BackgroundThe surplus of glycerol has increased remarkably as a main byproduct during the biofuel’s production. Exploiting an alternative route for glycerol utilization is significantly important for sustainability of biofuels.ResultsA novel biocatalyst that could be prepared from glycerol for producing 2-oxo-carboxylates was developed. First, Pseudomonas putida KT2440 was reconstructed by deleting lldR to develop a mutant expressing the NAD-independent lactate dehydrogenases (iLDHs) constitutively. Then, the Vitreoscilla hemoglobin (VHb) was heterologously expressed to further improve the biotransformation activity. The reconstructed strain, P. putida KT2440 (ΔlldR)/pBSPPcGm-vgb, exhibited high activities of iLDHs when cultured with glycerol as the carbon source. This cost-effective biocatalyst could efficiently produce pyruvate and 2-oxobutyrate from dl-lactate and dl-2-hydroxybutyrate with high molar conversion rates of 91.9 and 99.8 %, respectively.ConclusionsThe process would not only be a promising alternative for the production of 2-oxo-carboxylates, but also be an example for preparation of efficient biocatalysts for the value-added utilization of glycerol.

Coexistence of two d‐lactate‐utilizing systems in Pseudomonas putida KT2440

“…This operon encodes a lactate permease LldP (PP4735), an l ‐iLDH (PP4736) and a putative Fe‐S d ‐iLDH (PP4737). The expression of lldD and lldE is regulated by the regulator LldR encoded by pp4734 upstream the operon (Wang et al ., ). d ‐iLDH and l ‐iLDH are induced coordinately in Pseudomonas strains including P. aeruginosa , P. putida and P. stutzeri (O'Brien, ; Ma et al ., ; Gao et al ., ).…”

Preparation of Carriers Based on ZnO Nanoparticles Decorated on Graphene Oxide (GO) Nanosheets for Efficient Immobilization of Lipase from Candida rugosa

“…Biocatalysts possess excellent properties in terms of efficient catalytic activity, exclusion of undesirable side reactions, operations under mild conditions, and different types of stereoselectivity in some chemical reactions, such as oxidation-reduction [ 1 ], hydrolysis [ 2 ] and esterification [ 3 ]. To date biocatalysts have been widely used in applications including the synthesis of structured lipids [ 4 ], synthesis of pharmaceutical intermediates [ 5 ] and biofuel production [ 6 ]. Among all commercialized enzymes, one of the most popular enzymes, lipases (triacylglycerol ester hydrolases, EC 3.1.1.3) are widely used as adaptable biocatalysts [ 7 , 8 , 9 , 10 ] to catalyze a number of reactions making lipases unique biocatalysts in the chemistry, food, agrochemical, biotechnology and pharmaceutical industries due to their excellent regio-, chemo-, and stereoselective properties [ 11 ].…”

Fermentative Production of N-Methylglutamate From Glycerol by Recombinant Pseudomonas putida

“…The application of P. putida as glycerol utilizing host benefits from its tolerance to impurities present in crude glycerol, which may pose challenges for production with other hosts (Meiswinkel et al, 2013 ; Nguyen et al, 2013 ). Therefore, P. putida has been used for glycerol-based production of oxo-carboxylates (Wang et al, 2015 ), polyhydroxyalkanoates (Wang and Nomura, 2010 ; Poblete-Castro et al, 2014 ; Wang et al, 2014 ) or p -hydroxybenzoate (Verhoef et al, 2007 ). The molecular reason why glycerol is preferred over glucose is still not solved.…”