Use of Corn-Steep Water Effluent as a Promising Substrate for Lactic Acid Production by Enterococcus faecium Strain WH51-1

Abstract

Various challenges facing the industrial production of bio-based lactic acid (LA) such as cost of raw materials and nitrogen sources, as well as contamination risk by mesophilic and neutrophilic producers, should be overcome for the commercial production. This study aimed to investigate the feasibility of corn steep water (CSW) as a raw material for LA production using a newly thermo-alkali-tolerant lactic acid bacterium. The physicochemical characteristics of CSW were investigated. The high carbohydrates, proteins, amino acids, vitamins, essential elements, minerals, and non-protein nitrogenous compounds content confirmed that the CSW is a promising substrate for LA production. Out of 67 bacterial isolates, Enterococcus faecium WH51-1 was selected based on its tolerance to high temperatures and inhibitory compounds (sodium metabisulfate, sodium chloride, sodium acetate, and formic acid). Fermentation factors including sugar concentration, temperature, inoculum size, and neutralizing agents were optimized for LA production. Lactic acid concentration of about 44.6 g/L with a high yield (0.89 ± 0.02 g/g) was obtained using 60 g/L of CSW sugar, inoculum size 10% (v/v), 45 °C, and sodium hydroxide or calcium carbonate as a neutralizing agent. These results demonstrated the potential of strain WH51-1 for LA production using CSW effluent as raw material.

Contribution of Fermentation Technology to Building Blocks for Renewable Plastics

“…Pediococcus acidilactici, for instance, was engineered to use lignocellulosic biomass (corn stover and wheat straw) by Qiu et al [156,157], reaching high titers of D-lactic acid and L-lactic acid, with 97.3 and 130.8 g/L, respectively. The recent strategy to minimize contamination risk and facilitate non-sterilization lactic acid fermentation is using alkali-and thermo-tolerance strains [158]. They isolated Enterococcus faecium WH51-1, and successfully produced 44.6 g/L lactic acid with a yield of 0.89 g/g, from corn steep water at high temperature (45 • C) and pH (9.0).…”

Evaluate the Toxicity of Pyrethroid Insecticide Cypermethrin before and after Biodegradation by Lysinibacillus cresolivuorans Strain HIS7

“…On the other hand, the addition of glycerol as an extra carbon source led to reducing the degradation percentages to 54.2%. The decreasing of biodegradation percentages in the presence of extra carbon sources with an increase of bacterial growth can be attributed to catabolite repression caused by extra carbon sources [46,47]. Interestingly, the L. cresolivuorans strain HIS7 exhibits high efficacy to degrade cypermethrin in the presence of different nitrogen sources.…”

l‐Lactate oxidase‐mediated removal of l‐lactic acid derived from fermentation medium for the production of optically pure D‐lactic acid

“…As an alternative cheap nitrogen source, many authors have demonstrated the utility of corn steep liquor (CSL), which is occurred in starch manufacturing process from corns [ 16 ] in lactic acid production. [ 17–20 ] Wee et al. [ 18 ] reported that the addition of 30 g L –1 of CSL could reduce the concentration of yeast extract to 1 g L –1 in l ‐lactic acid fermentation from starch hydrolysate using Enterococcus faecalis RKY1.…”

“…As an alternative cheap nitrogen source, many authors have demonstrated the utility of corn steep liquor (CSL), which is occurred in starch manufacturing process from corns [16] in lactic acid production. [17][18][19][20] Wee et al [18] reported that the addition of 30 g L -1…”