Monascus ruber as cell factory for lactic acid production at low pH

2017 ◽  
Vol 42 ◽  
pp. 66-73 ◽  
Author(s):  
Ruud A. Weusthuis ◽  
Astrid E. Mars ◽  
Jan Springer ◽  
Emil JH Wolbert ◽  
Hetty van der Wal ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Low Ph ◽  
Cell Factory ◽  
Monascus Ruber

scholarly journals Improvement of Lactic Acid Production in Saccharomyces cerevisiae by Cell Sorting for High Intracellular pH

2006 ◽  
Vol 72 (8) ◽  
pp. 5492-5499 ◽  
Author(s):  
Minoska Valli ◽  
Michael Sauer ◽  
Paola Branduardi ◽  
Nicole Borth ◽  
Danilo Porro ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Lactic Acid ◽  
Intracellular Ph ◽  
Cell Sorting ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Low Ph ◽  
The Mean ◽  
High Level ◽  
Lactate Dehydrogenases

ABSTRACT Yeast strains expressing heterologous l-lactate dehydrogenases can produce lactic acid. Although these microorganisms are tolerant of acidic environments, it is known that at low pH, lactic acid exerts a high level of stress on the cells. In the present study we analyzed intracellular pH (pHi) and viability by staining with cSNARF-4F and ethidium bromide, respectively, of two lactic-acid-producing strains of Saccharomyces cerevisiae, CEN.PK m850 and CEN.PK RWB876. The results showed that the strain producing more lactic acid, CEN.PK m850, has a higher pHi. During batch culture, we observed in both strains a reduction of the mean pHi and the appearance of a subpopulation of cells with low pHi. Simultaneous analysis of pHi and viability proved that the cells with low pHi were dead. Based on the observation that the better lactic-acid-producing strain had a higher pHi and that the cells with low pHi were dead, we hypothesized that we might find better lactic acid producers by screening for cells within the highest pHi range. The screening was performed on UV-mutagenized populations through three consecutive rounds of cell sorting in which only the viable cells within the highest pHi range were selected. The results showed that lactic acid production was significantly improved in the majority of the mutants obtained compared to the parental strains. The best lactic-acid-producing strain was identified within the screening of CEN.PK m850 mutants.

scholarly journals Plasticity of the Pyruvate Node Modulates Hydrogen Peroxide Production and Acid Tolerance in Multiple Oral Streptococci

2017 ◽  
Vol 84 (2) ◽  
Author(s):  
Xingqun Cheng ◽  
Sylvio Redanz ◽  
Nyssa Cullin ◽  
Xuedong Zhou ◽  
Xin Xu ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Environmental Conditions ◽  
Dental Plaque ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Acid Tolerance ◽  
Oral Bacteria ◽  
Low Ph ◽  
Content Type ◽  
Pyruvate Node

ABSTRACTCommensalStreptococcus sanguinisandStreptococcus gordoniiare pioneer oral biofilm colonizers. Characteristic for both is the SpxB-dependent production of H2O2, which is crucial for inhibiting competing biofilm members, especially the cariogenic speciesStreptococcus mutans. H2O2production is strongly affected by environmental conditions, but few mechanisms are known. Dental plaque pH is one of the key parameters dictating dental plaque ecology and ultimately oral health status. Therefore, the objective of the current study was to characterize the effects of environmental pH on H2O2production byS. sanguinisandS. gordonii.S. sanguinisH2O2production was not found to be affected by moderate changes in environmental pH, whereasS. gordoniiH2O2production declined markedly in response to lower pH. Further investigation into the pyruvate node, the central metabolic switch modulating H2O2or lactic acid production, revealed increased lactic acid levels forS. gordoniiat pH 6. The bias for lactic acid production at pH 6 resulted in concomitant improvement in the survival ofS. gordoniiat low pH and seems to constitute part of the acid tolerance response ofS. gordonii. Differential responses to pH similarly affect other oral streptococcal species, suggesting that the observed results are part of a larger phenomenon linking environmental pH, central metabolism, and the capacity to produce antagonistic amounts of H2O2.IMPORTANCEOral biofilms are subject to frequent and dramatic changes in pH.S. sanguinisandS. gordoniican compete with caries- and periodontitis-associated pathogens by generating H2O2. Therefore, it is crucial to understand howS. sanguinisandS. gordoniiadapt to low pH and maintain their competitiveness under acid stress. The present study provides evidence that certain oral bacteria respond to environmental pH changes by tuning their metabolic output in favor of lactic acid production, to increase their acid survival, while others maintain their H2O2production at a constant level. The differential control of H2O2production provides important insights into the role of environmental conditions for growth competition of the oral flora.

scholarly journals Techno-Economic Analysis of Alternative Designs for Low-pH Lactic Acid Production

2021 ◽  
Author(s):  
Andressa Neves Marchesan ◽  
Jean Felipe Leal Silva ◽  
Rubens Maciel Filho ◽  
Maria Regina Wolf Maciel
Keyword(s):  
Lactic Acid ◽  
Economic Analysis ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Low Ph ◽  
Alternative Designs

scholarly journals Production of Raw Starch-Digesting Amylolytic Preparation in Yarrowia lipolytica and Its Application in Biotechnological Synthesis of Lactic Acid and Ethanol

2020 ◽  
Vol 8 (5) ◽  
pp. 717
Author(s):  
Aleksandra Gęsicka ◽  
Monika Borkowska ◽  
Wojciech Białas ◽  
Paulina Kaczmarek ◽  
Ewelina Celińska
Keyword(s):  
Lactic Acid ◽  
Ethanol Production ◽  
Yarrowia Lipolytica ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Thermal Conditions ◽  
Cell Factory ◽  
The Novel ◽  
Microbial Cell Factory ◽  
Raw Starch

Sustainable economy drives increasing demand for raw biomass-decomposing enzymes. Microbial expression platforms exploited as cellular factories of such biocatalysts meet requirements of large-volume production. Previously, we developed Yarrowia lipolytica recombinant strains able to grow on raw starch of different plant origin. In the present study, we used the most efficient amylolytic strain as a microbial cell factory of raw-starch-digesting (RSD) amylolytic preparation composed of two enzymes. The RSD-preparation was produced in fed-batch bioreactor cultures. Concentrated and partly purified preparation was then tested in simultaneous saccharification and fermentation (SSF) processes with thermotolerant Kluyveromyces marxianus for ethanol production and Lactobacillus plantarum for production of lactic acid. These processes were conducted as a proof-of-concept that application of the novel RSD-preparation supports sufficient starch hydrolysis enabling microbial growth and production of targeted molecules, as the selected strains were confirmed to lack amylolytic activity. Doses of the preparation and thermal conditions were individually adjusted for the two processes. Additionally, ethanol production was tested under different aeration strategies; and lactic acid production process was tested in thermally pre-treated substrate, as well. Conducted studies demonstrated that the novel RSD-preparation provides satisfactory starch hydrolyzing activity for ethanol and lactic acid production from starch by non-amylolytic microorganisms.

scholarly journals Chirality Matters: Synthesis and Consumption of the d-Enantiomer of Lactic Acid by Synechocystis sp. Strain PCC6803

2015 ◽  
Vol 82 (4) ◽  
pp. 1295-1304 ◽  
Author(s):  
S. Andreas Angermayr ◽  
Aniek D. van der Woude ◽  
Danilo Correddu ◽  
Ramona Kern ◽  
Martin Hagemann ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactate Dehydrogenase ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Cell Factory ◽  
Growth Stages ◽  
Microbial Cell Factory ◽  
Content Type ◽  
Acid Consumption ◽  
Glycolate Dehydrogenase

ABSTRACTBoth enantiomers of lactic acid,l-lactic acid andd-lactic acid, can be produced in a sustainable way by a photosynthetic microbial cell factory and thus from CO2, sunlight, and water. Several properties of polylactic acid (a polyester of polymerized lactic acid) depend on the controlled blend of these two enantiomers. Recently, cyanobacteriumSynechocystissp. strain PCC6803 was genetically modified to allow formation of either of these two enantiomers. This report elaborates on thed-lactic acid production achieved by the introduction of ad-specific lactate dehydrogenase from the lactic acid bacteriumLeuconostoc mesenteroidesintoSynechocystis. A typical batch culture of this recombinant strain initially shows lactic acid production, followed by a phase of lactic acid consumption, until production “outcompetes” consumption at later growth stages. We show thatSynechocystisis able to used-lactic acid, but notl-lactic acid, as a carbon source for growth. Deletion of the organism's putatived-lactate dehydrogenase (encoded byslr1556), however, does not eliminate this ability with respect tod-lactic acid consumption. In contrast,d-lactic acid consumption does depend on the presence of glycolate dehydrogenase GlcD1 (encoded bysll0404). Accordingly, this report highlights the need to match a product of interest of a cyanobacterial cell factory with the metabolic network present in the host used for its synthesis and emphasizes the need to understand the physiology of the production host in detail.

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