Direct lactic acid fermentation: Focus on simultaneous saccharification and lactic acid production

Abstract Objective A primary drawback to simultaneous saccharification and fermentation (SSF) processes is the incompatibility of the temperature and pH optima for the hydrolysis and fermentation steps—with the former working best at 50–55 °C and pH 4.5–5.5. Here, nine thermophilic Bacillus and Parageobacillus spp. were evaluated for growth and lactic acid fermentation at high temperature and low pH. The most promising candidate was then carried forward to demonstrate SSF using the cellulosic fraction from municipal solid waste (MSW) as a feedstock. Results B. smithii SA8Eth was identified as the most promising candidate and in a batch SSF maintained at 55 °C and pH 5.0, using a cellulase dose of 5 FPU/g glucan, it produced 5.1 g/L lactic acid from 2% (w/v) MSW cellulosic pulp in TSB media. Conclusion This work has both scientific and industrial relevance, as it evaluates a number of previously untrialled bacterial hosts for their compatibility with lignocellulosic SSF for lactic acid production and successfully identifies B. smithii as a potential candidate for such a process.

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A study on Lactic Acid fermentation of Sugar Palm (Arenga Pinnata) sap by Lactobacillus Casei

Science and Technology Development Journal ◽

10.32508/stdj.v17i2.1349 ◽

2014 ◽

Vol 17 (2) ◽

pp. 65-71

Author(s):

Nhat Minh Dang ◽

Trung Quang Nguyen

Keyword(s):

Lactic Acid ◽

Calcium Carbonate ◽

Ammonium Sulphate ◽

Acid Production ◽

Lactobacillus Casei ◽

Lactic Acid Production ◽

Lactic Acid Fermentation ◽

Microbial Culture ◽

Acid Fermentation ◽

Lower Ability

This study aimed to evaluate the effect of various factors on the yield of lactic acid fermentation using sap from sugar palm and Lactobacillus casei. The sugar palm sap after harvesting, pretreatment was added with ammonium sulphate, calcium carbonate and microbial culture at density of 109 cells/ml and let fermented for acid lactic production. The results of the experiments showed that the culture size, amount of added ammonium sulphate and calcium carbonate had significant effect on lactic acid production. The most appropriate parameters determined were culture size of 5%, ammonium sulphate of 3.0 g/l and calcium carbonate of 4.0 g/l. Meanwhile, the optimum period of fermentation was 100 h, which gave the yield of lactic acid production of 22.30 g. Lactobacillus casei was considered to have lower ability to effectively produce lactic acid from sugar palm sap compared to Lactobacillus plantarum

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Statistical Optimization of Alkali Pretreatment to Improve Sugars Recovery from Spent Coffee Grounds and Utilization in Lactic Acid Fermentation

Processes ◽

10.3390/pr9030494 ◽

2021 ◽

Vol 9 (3) ◽

pp. 494 ◽

Cited By ~ 1

Author(s):

Kang Hyun Lee ◽

Ye Won Jang ◽

Jeongho Lee ◽

Seunghee Kim ◽

Chulhwan Park ◽

...

Keyword(s):

Lactic Acid ◽

Enzymatic Hydrolysis ◽

Lactic Acid Production ◽

Complex Loading ◽

Lactic Acid Fermentation ◽

Optimum Conditions ◽

Spent Coffee Grounds ◽

Alkali Pretreatment ◽

Acid Fermentation ◽

Coffee Grounds

Biorefinery, which utilizes carbon-neutral biomass as a resource, is attracting attention as a significant alternative in a modern society confronted with climate change. In this study, spent coffee grounds (SCGs) were used as the feedstock for lactic acid fermentation. In order to improve sugar conversion, alkali pretreatment was optimized by a statistical method, namely response surface methodology (RSM). The optimum conditions for the alkali pretreatment of SCGs were determined as follows: 75 °C, 3% potassium hydroxide (KOH) and a time of 2.8 h. The optimum conditions for enzymatic hydrolysis of pretreated SCGs were determined as follows: enzyme complex loading of 30-unit cellulase, 15-unit cellobiase and 50-unit mannanase per g biomass and a reaction time of 96 h. SCG hydrolysates were used as the carbon source for Lactobacillus cultivation, and the conversions of lactic acid by L. brevis ATCC 8287 and L. parabuchneri ATCC 49374 were 40.1% and 55.8%, respectively. Finally, the maximum lactic acid production by L. parabuchneri ATCC 49374 was estimated to be 101.2 g based on 1000 g of SCGs through the optimization of alkali pretreatment and enzymatic hydrolysis.

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