Selection of the StrainLactobacillus acidophilusATCC 43121 and Its Application to Brewers’ Spent Grain Conversion into Lactic Acid

Abstract

Six Lactobacillus strains were analyzed to select a bacterium for conversion of brewers' spent grain (BSG) into lactic acid. Among the investigated strains, L. acidophilus ATCC 43121 showed the highest yield of lactic acid production (16.1 g/L after 48 hours) when grown in a synthetic medium. It was then analyzed for its ability to grow on the hydrolysates obtained from BSG after acid-alkaline (AAT) or aqueous ammonia soaking (AAS) pretreatment. The lactic acid production by L. acidophilus ATCC 43121 through fermentation of the hydrolysate from AAS treated BSG was 96% higher than that from the AAT treated one, although similar yields of lactic acid per consumed glucose were achieved due to a higher (46%) glucose consumption by L. acidophilus ATCC 43121 in the AAS BSG hydrolysate. It is worth noting that adding yeast extract to the BSG hydrolysates increased both the yield of lactic acid per substrate consumed and the volumetric productivity. The best results were obtained by fermentation of AAS BSG hydrolysate supplemented by yeast extract, in which the strain produced 22.16 g/L of lactic acid (yield of 0.61 g/g), 27% higher than the value (17.49 g/L) obtained in the absence of a nitrogen source.

Fed-batch l -(+)-lactic acid fermentation of brewer's spent grain hydrolysate

“…b). Liguori et al achieved similar reducing sugar utilization (37.4 g) in fermentation of BSG hydrolysate with an initial reducing sugar concentration of 50 g/L and yeast extract addition (12.5 g/L). L. rhamnosus cell viability increased until the end of fermentation (by 19.7%) and was 9.7 log CFU/mL after 36 h of fermentation.…”

“…Mussatto et al (23) obtained a similar LA concentration (35.5 g/L) in fermentation of BSG hydrolysate with initial reducing sugar concentration of~50 g/L, however with the addition of MRS broth nutrients (containing 5 g/L of yeast extract, without glucose), and also with pH control. In LA fermentation of BSG hydrolysate (containing 50 g/L of glucose and 12.5 g/L of yeast extract), Liguori et al (24) obtained significantly lower LA concentration (22.2 g/L) in comparison with the results achieved in our previous study (22) for batch fermentation of BSG hydrolysate (containing 54 g/L of glucose) with 10 g/L of yeast extract (35.6 g/L was achieved LA concentration) and also in this study in batch fermentation of BSG hydrolysate (with 54 g/L of reducing sugar and 50 g/L of yeast extract). During 36 h of fermentation 43.1 g of reducing sugar was utilized (Fig.…”

Waste Degradation and Utilization by Lactic Acid Bacteria: Use of Lactic Acid Bacteria in Production of Food Additives, Bioenergy and Biogas

“…Generation of the desired metabolite through fermentation of hydrolysate resulting from BSG pretreatment with aqueous ammonia was 96% higher than that following acid-alkaline treatment and constituted 17.49 g/L. The maximum value was obtained after addition of nitrogen source (yeast extract) to aqueous ammonia-treated BSG (22.16 g/L) [123]. Additional use of invertase from grape juice for sucrose hydrolysis of canned pineapple syrup, a food processing waste, resulted in lactic acid concentrations 20 and 92 g/L generated by L. lactis from 20 and 100 g total sugars/L [124].…”

Integrated biorefinery fromArthrospira platensisbiomass as feedstock for bioethanol and lactic acid production

“…The lactobacillus strain adopted for lactic acid production was L. acidophilus ATCC 43121 selected in our previous work (Liguori et al, 2015b). De Man, Rogosa and Sharpe broth (MRS) was used as the growth medium for the inoculum.…”

“…Based on this, the aim of this work was to analyze the strains Saccharomyces cerevisiae LPB-287 (Liguori et al, 2015a) and Lactobacillus acidophilus ATCC 43121 (Liguori et al, 2015b) for their ability to grow on the A. platensis residual biomass after high value metabolites extraction by either supercritical fluid extraction (SFE) or microwave-assisted extraction (MAE) and produce ethanol and lactic acid, respectively.…”