Lactic acid production in a continuous culture using lignocellulosic hydrolysate as a substrate. Identification of a physiological model

1996 ◽  
Vol 41 (2) ◽  
pp. 211-215 ◽  
Author(s):  
K. Melzoch ◽  
J. Votruba ◽  
J. Schwippel ◽  
M. Rychtera ◽  
V. Hábová
Keyword(s):  
Lactic Acid ◽  
Continuous Culture ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Physiological Model ◽  
Lignocellulosic Hydrolysate ◽  
Substrate Identification

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 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.

scholarly journals Efficient Lactic Acid Production from Dilute Acid Pretreated Lignocellulosic Biomass by a Synthetic Consortia of Engineered Pseudomonas Putida and Bacillus Coagulans

2021 ◽  
Author(s):  
Lihua Zou ◽  
Shuiping Ouyang ◽  
Yueli Hu ◽  
Zhaojuan Zheng ◽  
Jia Ouyang
Keyword(s):  
Lactic Acid ◽  
Pseudomonas Putida ◽  
Lignocellulosic Biomass ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Value Added ◽  
Bacillus Coagulans ◽  
Microbial Consortia ◽  
Lignocellulosic Hydrolysate ◽  
High Concentration

Abstract Background Lignocellulosic biomass is an attractive and sustainable alternative to petroleum-based feedstock for the production a range of biochemicals, and a pretreatment is generally regarded to be indispensable for its bio-refinery. Nevertheless, various inhibitors that severely hindered the growth and fermentation of microorganisms were produced inevitably during the pretreatment of lignocellulose. Presently, a single microorganism that can tolerate toxic mixtures of pretreatment hydrolysate while effectively transforming sugar components into valuable compound is less well reported. Alternatively, microbial co-culture provides a simpler and more efficacious way to realize this goal via distributing metabolic tasks among proper strains. Results In this study, a novel synthetic microbial consortia, 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 high-toxic lignocellulosic hydrolysate. The engineered P. putida with deletion of sugar metabolism pathway was suggested to be unable to consume the major fermentable sugars of lignocellulosic hydrolysate, but can rapidly remove inhibitors in hydrolysate. With detoxification using engineered P. putida for 24 h, the pretreated hydrolysate was fermented into 35.8 g/L of lactic acid by B. coagulans with a yield of 90%. The fermentation performance of microbial co-culture was significantly improved than that single culture of B. coagulans without lactic acid production. Conclusions The microbial coculture system constructed by this study demonstrated strong potential of the process for biosynthesis of valuable product from lignocellulosic hydrolysate containing high concentration of complex inhibitors by specifically recruited consortia of robust microorganisms with desirable characteristics and also provided a feasible and attractive method for bioconversion of lignocellulosic biomass to other value-added biochemicals.

scholarly journals Protective effect of titanium tetrafluoride and silver diamine fluoride on radiation-induced dentin caries in vitro

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Beatriz Martines de Souza ◽  
Mayara Souza Silva ◽  
Aline Silva Braga ◽  
Patrícia Sanches Kerges Bueno ◽  
Paulo Sergio da Silva Santos ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Protective Effect ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Negative Control ◽  
Titanium Tetrafluoride ◽  
Silver Diamine Fluoride ◽  
Dentin Caries ◽  
Radiation Induced

AbstractThis in vitro study evaluated the protective effect of titanium tetrafluoride (TiF4) varnish and silver diamine fluoride (SDF) solution on the radiation-induced dentin caries. Bovine root dentin samples were irradiated (70 Gy) and treated as follows: (6 h): 4% TiF4 varnish; 5.42% NaF varnish; 30% SDF solution; placebo varnish; or untreated (negative control). Microcosm biofilm was produced from human dental biofilm (from patients with head-neck cancer) mixed with McBain saliva for the first 8 h. After 16 h and from day 2 to day 5, McBain saliva (0.2% sucrose) was replaced daily (37 °C, 5% CO2) (biological triplicate). Demineralization was quantified by transverse microradiography (TMR), while biofilm was analyzed by using viability, colony-forming units (CFU) counting and lactic acid production assays. The data were statistically analyzed by ANOVA (p < 0.05). TiF4 and SDF were able to reduce mineral loss compared to placebo and the negative control. TiF4 and SDF significantly reduced the biofilm viability compared to negative control. TiF4 significantly reduced the CFU count of total microorganism, while only SDF affected total streptococci and mutans streptococci counts. The varnishes induced a reduction in lactic acid production compared to the negative control. TiF4 and SDF may be good alternatives to control the development of radiation-induced dentin caries.

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