Production of succinate from simply purified crude glycerol by engineered Escherichia coli using two-stage fermentation

Abstract

Background: Crude glycerol is a main by-product from biodiesel production, and efficient utilization of crude glycerol will bring significant economic and environmental benefits. However, the complex compositions of crude glycerol may impair the cellular growth and inhibit the crude glycerol consumption. Therefore, it is necessary to find a simple method to treat the crude glycerol and release the inhibition on cell metabolism. Results: The simply purified crude glycerol by activated carbon can be used as the carbon source to produce succinate in two-stage fermentation by the engineered Escherichia coli strain, MLB (ldhA − , pflB −) expressing phosphoenolpyruvate carboxykinase. In the flask experiments, succinate production from crude glycerol without treatment was less than that from pure glycerol. However, in the experiments of 1.5-L bioreactor, little succinate was produced in crude glycerol. The simply purified crude glycerol was used as carbon source for succinate production, and the glycerol consumption and succinate production were enhanced greatly. The succinate produced from the simply purified crude glycerol reached 566.0 mM, which was about ten times higher as that of non-purified one (50.3 mM). The succinate yield of the anaerobic stage achieved 0.97 mol/mol, which was 97% of the theoretical yield. Conclusion: The treatment of crude glycerol by activated carbon could effectively release the inhibition on the glycerol consumption and succinate production of the engineered E. coli strains, so that the fermentation result of the treated crude glycerol was similar as the pure glycerol. The results showed that the metabolically engineered E. coli strains have great potential to produce succinate from crude glycerol.

High-Level Production of Succinic Acid from Crude Glycerol by a Wild Type Organism

“…Established microorganisms for the production of succinic acid are Actinobacillus succinogenes, Corynebacterium glutamicum, Anaerobiospirillum succiniciproducens, Mannheimia succiniciproducens, Basfia succiniciproducens, Yarrowia lipolytica, or Escherichia coli. However, Corynebacterium glutamicum, Anaerobiospirillum succiniciproducens, Mannheimia succiniciproducens, Basfia succiniciproducens, Yarrowia lipolytica, as well as Escherichia coli, are mainly used in the form of genetically-modified organisms [12,[24][25][26][27][28][29][30][31]. The highest final titer of 198 g L −1 succinic acid is achieved with glycerol and a genetically-modified (GMO) Yarrowia lipolytica [24].…”

“…The investigations regarding crude glycerol as sole carbon sources have also been carried out. According to Li et. al (2018), the treatment of crude glycerol by activated carbon effectively released the inhibition on the glycerol consumption and succinate production of the genetically engineered E. coli strains, and the fermentation result of the treated crude glycerol was with 566.0 mM succinic acid compared to the usage of pure glycerol [31].…”

Diverse Profile of Fermentation Byproducts From Thin Stillage

“…However, SA fermentation using industrial and agricultural byproducts such as corn steep solids from wet milling (Rogers et al, 2013) or crude glycerol from biodiesel production has been demonstrated, which is consistent with the potential use of TS or other agro-industrial residues for SA production. Typical examples of industrially relevant bacteria for SA production are Gammaproteobacteria including strains of Actinobacillus, Basfia, Escherichia, and Anaerobiospirillum (Li et al, 2016(Li et al, , 2018Nghiem et al, 2017;Zheng et al, 2021), and also Corynebacterium from the phylum Actinobacteria (Litsanov et al, 2013). While relatives of these genera were absent from the microbial communities in this study (Supplementary Table 1), the abundant taxa from R3 LowSRT represent a potential source for cultivating novel strains for SA production (Figure 3).…”

Efficient l‐lactic acid production from purified sweet sorghum juice coupled with soybean hydrolysate as nitrogen source by Lactobacillus thermophilus A69 strain

“…After treatment by hot lime clarification, the purified sweet sorghum juice showed lower color value . Very little information is available on the relationship between the color value of sweet sorghum juice and l ‐lactic acid accumulation by lactic acid bacteria, but Li et al found that the color value of crude glycerol could be efficiently decreased by activated carbon, and the succinate produced from simply purified crude glycerol by Escherichia coli strain MLB was markedly higher than that from non‐purified crude glycerol. Unfortunately, it is unclear whether the decreased color value of crude glycerol can influence succinate production by E. coli strain MLB.…”