Effects of medium supplementation and pH control on lactic acid production from brewer's spent grain

SixLactobacillusstrains were analyzed to select a bacterium for conversion of brewers’ spent grain (BSG) into lactic acid. Among the investigated strains,L. acidophilusATCC 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 byL. acidophilusATCC 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 byL. acidophilusATCC 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.

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Mathematical Modeling of Lactobacillus paracasei CBA L74 Growth during Rice Flour Fermentation Performed with and without pH Control

Applied Sciences ◽

10.3390/app11072921 ◽

2021 ◽

Vol 11 (7) ◽

pp. 2921

Author(s):

Rosa Colucci Cante ◽

Marianna Gallo ◽

Federica Nigro ◽

Francesca Passannanti ◽

Andrea Budelli ◽

...

Keyword(s):

Mathematical Modeling ◽

Growth Rate ◽

Lactic Acid ◽

Specific Growth Rate ◽

Biomass Production ◽

Acid Production ◽

Specific Growth ◽

Lactic Acid Production ◽

Rice Flour ◽

Ph Control

The mathematical modeling of fermentation processes allows for the formulation of predictions about the kinetics of biomass growth and metabolite production as well as setting or verifying the best operative conditions in view of the economical convenience of the process. For this purpose, we performed a kinetic study of a rice flour fermentation process using Lactobacillus paracasei CBA L74 with and without pH control; the pH value was set to 5.8 under pH control. Monod, Logistic, and Contois models were proposed to describe the bacterial growth rate in both conditions. The best mathematical model, which was able to describe the experimental data obtained without pH control, was the Contois model, as the specific growth rate was influenced by both the glucose reduction (from 14.31 g/L to 10.22 g/L) and the biomass production (2 log growth) that occurred during fermentation. Conversely, when pH control was implemented, both Monod and Contois models satisfactorily described the specific growth rate trend. The estimated kinetic parameters confirmed that biomass production (2 log growth) and glucose consumption (from 14.31 g/L to 6.06 g/L) did not affect the microorganism’s growth capacity when the fermenting medium was maintained at an optimal pH. The lactic acid production rate described by the Luedeking–Piret model did not appear to be linked to growth in the absence of pH control while, on the other hand, this model was unsuitable for describing the experimental lactic acid concentration when pH control was applied. The kinetic modeling of lactic acid production and the percentage of added glucose in the protocol with controlled pH will be optimized in the future.

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Optimization of fermentation conditions for high L-lactic acid production from cellobiose by entercoccus mundtii QU 25: Impact of pH control and temperature on cell growth and changes in metabolites

2010 International Conference on Environmental Engineering and Applications ◽

10.1109/iceea.2010.5596153 ◽

2010 ◽

Author(s):

Mohamed Ali Abdel-Rahman ◽

Takeshi Zendo ◽

Kenji Sonomoto ◽

Yukihiro Tashiro

Keyword(s):

Lactic Acid ◽

Cell Growth ◽

Acid Production ◽

Lactic Acid Production ◽

Ph Control ◽

Fermentation Conditions ◽

Optimization Of Fermentation

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Lactic acid fermentation of brewer's spent grain hydrolysate byLactobacillus rhamnosuswith yeast extract addition and pH control

Journal of the Institute of Brewing ◽

10.1002/jib.403 ◽

2017 ◽

Vol 123 (1) ◽

pp. 98-104 ◽

Cited By ~ 11

Author(s):

Jelena Pejin ◽

Miloš Radosavljević ◽

Sunčica Kocić-Tanackov ◽

Aleksandra Djukić-Vuković ◽

Ljiljana Mojović

Keyword(s):

Lactic Acid ◽

Yeast Extract ◽

Ph Control ◽

Lactic Acid Fermentation ◽

Acid Fermentation ◽

Brewer’S Spent Grain ◽

Spent Grain

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Efficient utilization of hydrolysates from steam-exploded gardening residues for lactic acid production by optimization of enzyme addition and pH control

Waste Management ◽

10.1016/j.wasman.2020.04.003 ◽

2020 ◽

Vol 107 ◽

pp. 235-243 ◽

Cited By ~ 9

Author(s):

Enrique Cubas-Cano ◽

Cristina González-Fernández ◽

Ignacio Ballesteros ◽

Elia Tomás-Pejó

Keyword(s):

Lactic Acid ◽

Acid Production ◽

Lactic Acid Production ◽

Ph Control ◽

Efficient Utilization

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Industrial Performance of Several Lachancea thermotolerans Strains for pH Control in White Wines from Warm Areas

Microorganisms ◽

10.3390/microorganisms8060830 ◽

2020 ◽

Vol 8 (6) ◽

pp. 830 ◽

Cited By ~ 2

Author(s):

Cristian Vaquero ◽

Iris Loira ◽

María Antonia Bañuelos ◽

José María Heras ◽

Rafael Cuerda ◽

...

Keyword(s):

Lactic Acid ◽

Acid Production ◽

Ethanol Yield ◽

Sugar Content ◽

Lactic Acid Production ◽

Ph Control ◽

Fermentation Conditions ◽

High Ph ◽

Industrial Performance ◽

Lachancea Thermotolerans

In the current scenario of climatic warming, the over-ripening of grapes increases the sugar content, producing flat and alcoholic wines with low acidity, high pH and low freshness. Additionally, a high pH makes wines more chemically and microbiologically unstable, requiring a higher sulphite content for preservation. Some strains of Lachancea thermotolerans can naturally lower the pH of wine by producing lactic acid from sugars; this pH reduction can reach 0.5 units. The industrial performance of four selected strains has been compared with that of two commercial strains and with that of Saccharomyces cerevisiae. The yeasts were assessed under variable oenological conditions, measuring lactic acid production and fermentative performance at two fermentation temperatures (17 and 27 °C), and in the presence or absence of sulphites (25 and 75 mg/L). Lactic acid production depends on yeast populations, with higher concentrations being reached when the microbial population is close to or above 7-log CFU/mL. A temperature effect on acidification can also be observed, being more intense at higher fermentation temperatures for most strains. Ethanol yield ranged from 7–11% vol., depending on the fermentation conditions (temperature and SO2) at day 12 of fermentation, compared with 12% for the S. cerevisiae control in micro-fermentations. The production of fermentative esters was higher at 27 °C compared with 17 °C, which favoured the production of higher alcohols. Volatile acidity was moderate under all fermentation conditions with values below 0.4 g/L.

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