Enhancement of 1,3-propanediol production from industrial by-product by Lactobacillus reuteri CH53

Abstract

Background: 1,3-propanediol (1,3-PDO) is the most widely studied value-added product that can be produced by feeding glycerol to bacteria, including Lactobacillus sp. However, previous research reported that L. reuteri only produced small amounts and had low productivity of 1,3-PDO. It is urgent to develop procedures that improve the production and productivity of 1,3-PDO. Results:We identified a novel L. reuteri CH53 isolate that efficiently converted glycerol into 1,3-PDO, and performed batch co-fermentation with glycerol and glucose to evaluate its production of 1,3-PDO and other products. We optimized the fermentation conditions and nitrogen sources to increase the productivity. Fed-batch fermentation using corn steep liquor (CSL) as a replacement for beef extract led to 1,3-PDO production (68.32 ± 0.84 g/L) and productivity (1.27 ± 0.02 g/L/h) at optimized conditions (unaerated and 100 rpm). When CSL was used as an alternative nitrogen source, the activity of the vitamin B12-dependent glycerol dehydratase (dhaB) and 1,3-propanediol oxidoreductase (dhaT) increased. Also, the productivity and yield of 1,3-PDO increased as well. These results showed the highest productivity in Lactobacillus species. In addition, hurdle to 1,3-PDO production in this strain were identified via analysis of the half-maximal inhibitory concentration for growth (IC50) of numerous substrates and metabolites. Conclusions:We used CSL as a low-cost nitrogen source to replace beef extract for 1,3-PDO production in L. reuteri CH53. These cells efficiently utilized crude glycerol and CSL to produce 1,3-PDO. This strain has great promise for the production of 1,3-PDO because it is generally recognized as safe (GRAS) and non-pathogenic. Also, this strain has high productivity and high conversion yield.

The Biocatalytic Production of 3-Hydroxypropionaldehyde and Evaluation of Its Stability

“…A previous study also reported reactivation of dhaB by vitamin B12 and ATP in L. reuteri [25]. In particular, L. reuteri can produce vitamin B12 via glucose metabolism [26][27][28]. However, during the bioconversion of 3-HPA from aqueous glycerol, this species is unable to produce vitamin B12 and ATP because it lacks the ability to use glycerol as a carbon source to produce vitamin B12 and ATP [20,27].…”

“…Mixtures containing samples and standards were incubated for 20 min in a water bath at 37 • C, and OD 560 nm was then measured [14]. The enzymatic activities of dhaB and dhaT were measured as previously described [28].…”

Sequential fed-batch fermentation of 1,3-propanediol from glycerol by Clostridium butyricum DL07

“…Besides, reducing the production cost of the 1,3-PDO will make the factory profitable. The costs of carbon, organic nitrogen source and aerating nitrogen are the main obstacles to industrial production of 1,3-PDO (Ju et al,2020;Wischral et al,2016).…”

Editorial: Microbial Production of Biopolyesters and Their Building Blocks: Opportunities and Challenges

“…Moreover, the diversity of bio-monomers has increased in recent years ( Taguchi and Matsumoto, 2020 ). In addition to well-known bio-organic acids (lactic acid and succinic acid), bio-diols like 1,4-butanediol and 1,3-propanediol, have achieved high-titer production using engineered strains ( Yim et al, 2011 ; Ju et al, 2020 ). These bio-monomers can be utilized as drop-in chemicals in the production of commercial polyesters like poly(butylene succinate) (PBS), poly(butylene terephthalate) (PBT), and poly(propylene terephthalate) (PPT).…”