Role of pH-regulation in lactic acid fermentation: Second steps in a process improvement

Hetényi, Kata; Németh, Áron; Sevella, B.

doi:10.1016/j.cep.2011.01.008

Cited by 51 publications

(24 citation statements)

References 17 publications

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“…With LA fermentations, pH control is crucial as the free LA, even at low concentrations, inhibits both cell growth and further LA formation . LA concentration increased significantly (by 15.1% at 5 g/L of BY to 32.8% at 50 g/L of BY) with yeast addition and pH control.…”

Section: Resultsmentioning

confidence: 99%

Use of spent brewer's yeast in L-(+) lactic acid fermentation

et al. 2019

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The application of by‐products from the brewing industry in lactic acid (LA) production was investigated in order to replace expensive nitrogen sources (such as yeast extract) with cheaper and renewable nitrogenous materials such as brewer's yeast (BY). In this study, brewer's spent grain (BSG) hydrolysate was used for L‐(+)‐LA fermentation by Lactobacillus rhamnosus ATCC 7469. The effect of pH control during the fermentation and the addition of various BY contents (5–50 g/L) in BSG hydrolysate on fermentation parameters was evaluated. BY addition significantly increased free amino nitrogen (FAN) concentration (by 25.2% at 5 g/L to 616% at 50 g/L). A strong positive correlation between FAN concentration in the hydrolysate and concentration of L‐(+)‐LA produced was observed (correlation coefficient of 0.913). A high cell viability of L. rhamnosus ATCC 7469 (1.95–3.32 × 109 CFU/mL at the end of fermentation) was achieved in all fermentations with the addition of brewer's yeast. The addition of BY increased L‐(+)‐lactic acid yield and volumetric productivity up to 8.4% (5 g/L) and 48.3% (50 g/L). The highest L‐(+)‐LA yield (89%) and volumetric productivity (0.89 g/L h−1) were achieved in fermentation of BSG hydrolysate with 50 g/L of BY. © 2019 The Institute of Brewing & Distilling

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Section: Resultsmentioning

confidence: 99%

Use of spent brewer's yeast in L-(+) lactic acid fermentation

et al. 2019

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“…In addition, the biotechnological production of LA has more benefits such as low cost of substrates, mild production conditions, and simple product recovery (5,6). So far, batch and fed-batch fermentations are still the leading processes of fermentative LA production (7)(8)(9)(10)(11). Although recent studies using either optimal microorganism strains or fermentation conditions were able to achieve a high level of final LA concentration in the fermentation broth of up to 225 g·L −1 , their volumetric productivities seldom exceeded 5 g·L −1 ·h −1 (7,8,10,12), which was caused by the long fermentation period of 50 to 200 h (7,8,12,13).…”

Section: Introductionmentioning

confidence: 96%

Lactic acid production in a membrane bioreactor system with thermophilicBacillus coagulans: fouling analysis of the used ceramic membranes

Fan

Ebrahimi

Quitmann

et al. 2015

Separation Science and Technology

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In lactic acid fermentation broth systems, membrane fouling is characterized as the crucial factor in limiting ceramic membrane lifetime and efficiency. This study aimed to find the limiting factor of this process and seek an effective solution. By quantitative analysis using resistance-in-series model, the cake layer resistance is demonstrated to be the dominant factor in a steady state. A cake compressibility index was measured as high as 2.09. Within the low transmembrane pressure range, the cake resistance was manipulated through crossflow velocity regulation to achieve a better membrane performance. A new correlation between flux and cell density was also introduced.

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“…To ensure the productivity of lactic acid, a suitable pH value for bacterial growth must be maintained at around 5-7 by addition of pH regulating agent (Hetényi et al, 2011;Hofvendahl and HahnHägerdal, 2000), and the responding metal lactates are produced. However, as an economical magnesium additive in food, drinks, dairy, flour and pharmaceutical industries (Lawless et al, 2003;Soliman and Abdel-Fattah, 2012), magnesium lactate is commonly made from neutralization reaction by purified lactic acid and magnesium base.…”

Section: Introductionmentioning

confidence: 99%