Lactic acid production in a cell retention continuous culture using lignocellulosic hydrolysate as a substrate

1997 ◽  
Vol 56 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Karel Melzoch ◽  
Jaroslav Votruba ◽  
Věra Hábová ◽  
Mojmı́r Rychtera
Keyword(s):  
Lactic Acid ◽  
Continuous Culture ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Lignocellulosic Hydrolysate ◽  
Cell Retention ◽  
A Cell

scholarly journals Dynamic Simulation of Continuous Mixed Sugars Fermentation with Increasing Cell Retention Time for Lactic Acid Production using Enterococcus mundtii QU 25

2020 ◽  
Author(s):  
Ying Wang ◽  
Ka-Lai Chan ◽  
Mohamed Ali Abdel-Rahman ◽  
Kenji Sonomoto ◽  
Shao-Yuan Leu
Keyword(s):  
Lactic Acid ◽  
Retention Time ◽  
Acid Production ◽  
Fermentation Process ◽  
Lactic Acid Production ◽  
Critical Role ◽  
Cell Retention ◽  
Mixed Sugars ◽  
Enterococcus Mundtii ◽  
Mixed Sugar

Abstract Background: Simultaneous and effective conversion of both pentose and hexoses in fermentation is a critical and challenging task toward the lignocellulosic economy. This study aims to investigate the feasibility of an innovative co-fermentation process featured with cell recycle unit (CF/CR) for mixed sugar utilization. A l-lactic acid producing strain Enterococcus mundtii QU 25 was applied in the continuous fermentation process to utilize the mixed sugar at different productivities over the changes of flowing conditions. Structured numerical platform were constructed with the experiments to optimize the biological process and clarify the cell metabolisms through kinetics analysis. The structured model, kinetic parameters, and achievement of the fermentation strategy shall provide new insights towards whole sugar fermentation via real-time monitoring for process control and optimization.Results: Significant carbon catabolite repression of co-fermentation using glucose/xylose mixture was overcome by replacing glucose with cellobiose, of which the consumption ratio of hexose to pentose was improved dramatically from 10.4:1 to 2.17:1. An outstanding product concentration of 65.15 g·L -1 and productivity of 13.03 g·L -1 ·h -1 were achieved with 50 g·L -1 cellobiose and 30 g·L -1 xylose, at an optimized dilution rate of 0.2 h -1 with gradually increased cell retention time. Among the total lactic acid production, xylose contributed to more than 34% of the mixed sugars, which was close to the related contents in agricultural residuals. The model successfully simulated the transition of sugar consumption, cell growth, and lactic acid production among the batch, continuous process, and CF/CR system.Conclusion: Cell retention time played a critical role in balancing pentose and hexose consumption, cell decay, and lactic acid production in the CF/CR process. With the increase of cell concentration, consumption of mixed sugars increased with the productivity of final products, hence the impacts of substrate inhibiting reduced. With the validated parameters, the model showed highest accuracy simulating the CF/CR process, of which significantly longer cell retention times over hydraulic retention time were tested.

scholarly journals Treatment with, Resveratrol, a SIRT1 Activator, Prevents Zearalenone-Induced Lactic Acid Metabolism Disorder in Rat Sertoli Cells

Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2474 ◽  
Author(s):  
Peirong Cai ◽  
Nannan Feng ◽  
Wanglong Zheng ◽  
Hao Zheng ◽  
Hui Zou ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Sertoli Cells ◽  
Reproductive System ◽  
Acid Production ◽  
Cell Metabolism ◽  
Lactic Acid Production ◽  
Male Reproductive System ◽  
Metabolism Disorder ◽  
A Cell ◽  
Sirt1 Activator

Zearalenone (ZEA) interferes with the function of the male reproductive system, but its molecular mechanism has yet to be completely elucidated. Sertoli cells (SCs) are important in the male reproductive system. Silencing information regulator 1 (SIRT1) is a cell metabolism sensor and resveratrol (RSV) is an activator of SIRT1. In this study we investigated whether SIRT1 is involved in the regulation of ZEA-induced lactate metabolism disorder in SCs. The results showed that the cytotoxicity of ZEA toward SCs increased with increasing ZEA concentration. Moreover, ZEA induced a decrease in the production of lactic acid and pyruvate of SCs and inhibited the expression of glycolytic genes and lactic acid production-related proteins. ZEA also led to a decreased expression of SIRT1 in energy receptors and decreased ATP levels in SCs. However, the ZEA-induced cytotoxicity and decline in lactic acid production in SCs were alleviated by the use of RSV, which is an activator of SIRT1. In summary, ZEA decreased lactic acid production in SCs, while the treatment with an SIRT1 activator, RSV, restored the inhibition of lactic acid production in SCs and reduced cytotoxicity of ZEA toward SCs.

scholarly journals Efficient lactic acid production from dilute acid-pretreated lignocellulosic biomass by a synthetic consortium of engineered Pseudomonas putida and Bacillus coagulans

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Lihua Zou ◽  
Shuiping Ouyang ◽  
Yueli Hu ◽  
Zhaojuan Zheng ◽  
Jia Ouyang
Keyword(s):  
Lactic Acid ◽  
Pseudomonas Putida ◽  
Lignocellulosic Biomass ◽  
Acid Production ◽  
Levulinic Acid ◽  
Lactic Acid Production ◽  
Value Added ◽  
Bacillus Coagulans ◽  
Lignocellulosic Hydrolysate ◽  
Acid Yield

Abstract Background Lignocellulosic biomass is an attractive and sustainable alternative to petroleum-based feedstock for the production of a range of biochemicals, and pretreatment is generally regarded as indispensable for its biorefinery. However, various inhibitors that severely hinder the growth and fermentation of microorganisms are inevitably produced during the pretreatment of lignocellulose. Presently, there are few reports on a single microorganism that can detoxify or tolerate toxic mixtures of pretreated lignocellulose hydrolysate while effectively transforming sugar components into valuable compounds. Alternatively, microbial coculture provides a simpler and more efficacious way to realize this goal by distributing metabolic functions among different specialized strains. Results In this study, a novel synthetic microbial consortium, which is composed of a responsible for detoxification bacterium engineered Pseudomonas putida KT2440 and a lactic acid production specialist Bacillus coagulans NL01, was developed to directly produce lactic acid from highly toxic lignocellulosic hydrolysate. The engineered P. putida with deletion of the sugar metabolism pathway was unable to consume the major fermentable sugars of lignocellulosic hydrolysate but exhibited great tolerance to 10 g/L sodium acetate, 5 g/L levulinic acid, 10 mM furfural and HMF as well as 2 g/L monophenol compound. In addition, the engineered strain rapidly removed diverse inhibitors of real hydrolysate. The degradation rate of organic acids (acetate, levulinic acid) and the conversion rate of furan aldehyde were both 100%, and the removal rate of most monoaromatic compounds remained at approximately 90%. With detoxification using engineered P. putida for 24 h, the 30% (v/v) hydrolysate was fermented to 35.8 g/L lactic acid by B. coagulans with a lactic acid yield of 0.8 g/g total sugars. Compared with that of the single culture of B. coagulans without lactic acid production, the fermentation performance of microbial coculture was significantly improved. Conclusions The microbial coculture system constructed in this study demonstrated the strong potential of the process for the biosynthesis of valuable products from lignocellulosic hydrolysates containing high concentrations of complex inhibitors by specifically recruiting consortia of robust microorganisms with desirable characteristics and also provided a feasible and attractive method for the bioconversion of lignocellulosic biomass to other value-added biochemicals.

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