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

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 494 ◽  
Author(s):  
Kang Hyun Lee ◽  
Ye Won Jang ◽  
Jeongho Lee ◽  
Seunghee Kim ◽  
Chulhwan Park ◽  
...  

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.

Author(s):  
Micaela G. Chacón ◽  
Christopher Ibenegbu ◽  
David J. Leak

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.


2008 ◽  
Vol 33 (4) ◽  
pp. 1173-1175
Author(s):  
Satoshi Noro ◽  
Tadashi Takahashi ◽  
Jyunji Ichita ◽  
Yasuhito Muranaka ◽  
Yoji Kato

2004 ◽  
Vol 69 (8-9) ◽  
pp. 625-634 ◽  
Author(s):  
Marica Rakin ◽  
Josip Baras ◽  
Maja Vukasinovic ◽  
Milan Maksimovic

The conditions for lactic acid fermentation based on a mixture of beetoot juice (Beta vulgaris L) and carrot juice (Daucus carota L) and different content of brewer?s yeast autolysate with Lactobacillus plantarum A112 and with Lactobacillus acidophilus NCDO 1748 has been studied. Both cultures showed good biochemical activity in these mixtures. The production of lactic acid has been stimulated using a higher content of brewer?s yeast autolysate. In these mixtures, L. plantarum A112 showed better growth and lactic acid production than L. acidophilus NCDO 1748. From the data obtained through chemical analyses of the fermented products, it can be seen that the mixture of beetroot and carrot juice and brewer?s yeast autolysate is richer in minerals (Ca, P, Fe) and ?-carotene than fermented beetroot juice with the same content of brewer?s yeast autolysate.


2014 ◽  
Vol 17 (2) ◽  
pp. 65-71
Author(s):  
Nhat Minh Dang ◽  
Trung Quang Nguyen

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


RSC Advances ◽  
2018 ◽  
Vol 8 (55) ◽  
pp. 31267-31274 ◽  
Author(s):  
Suan Shi ◽  
Jing Li ◽  
Wenjian Guan ◽  
David Blersch

Fish manure wastes are an effective nutrient source for lactic acid production using simultaneous saccharification and fermentation.


2010 ◽  
Vol 76 (13) ◽  
pp. 4277-4285 ◽  
Author(s):  
Abdullah-Al-Mahin ◽  
Shinya Sugimoto ◽  
Chihana Higashi ◽  
Shunsuke Matsumoto ◽  
Kenji Sonomoto

ABSTRACT The effects of nisin-induced dnaK expression in Lactococcus lactis were examined, and this expression was shown to improve stress tolerance and lactic acid fermentation efficiency. Using a nisin-inducible expression system, DnaK proteins from L. lactis (DnaK Lla ) and Escherichia coli (DnaK Eco ) were produced in L. lactis NZ9000. In comparison to a strain harboring the empty vector pNZ8048 (designated NZ-Vector) and one expressing dnaKLla (designated NZ-LDnaK), the dnaKEco -expressing strain, named NZ-EDnaK, exhibited more tolerance to heat stress at 40°C in GM17 liquid medium. The cell viability of NZ-Vector was reduced 4.6-fold after 6 h of heat treatment. However, NZ-EDnaK showed 13.5-fold increased viability under these conditions, with a very low concentration of DnaK Eco production. Although the heterologous expression of dnaKEco did not effect DnaK Lla production, heat treatment increased the DnaK Lla level 3.5- and 3.6-fold in NZ-Vector and NZ-EDnaK, respectively. Moreover, NZ-EDnaK showed tolerance to multiple stresses, including 3% NaCl, 5% ethanol, and 0.5% lactic acid (pH 5.47). In CMG medium, the lactate yield and the maximum lactate productivity of NZ-EDnaK were higher than the corresponding values for NZ-Vector at 30°C. Interestingly, at 40°C, these values of NZ-EDnaK were not significantly different from the corresponding values for the control strain at 30°C. Lactate dehydrogenase (LDH) activity was also found to be stable at 40°C in the presence of DnaK Eco . These findings suggest that the heterologous expression of dnaKEco enhances the quality control of proteins and enzymes, resulting in improved growth and lactic acid fermentation at high temperature.


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