Lactic acid production by Saccharomyces cerevisiae expressing a Rhizopus oryzae lactate dehydrogenase gene

2003 ◽  
Vol 30 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Christopher D. Skory
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Lactic Acid ◽  
Lactate Dehydrogenase ◽  
Acid Production ◽  
Rhizopus Oryzae ◽  
Lactic Acid Production ◽  
Dehydrogenase Gene

scholarly journals Efficient Production of l-Lactic Acid by Metabolically Engineered Saccharomyces cerevisiae with a Genome-Integrated l-Lactate Dehydrogenase Gene

2005 ◽  
Vol 71 (4) ◽  
pp. 1964-1970 ◽  
Author(s):  
Nobuhiro Ishida ◽  
Satoshi Saitoh ◽  
Kenro Tokuhiro ◽  
Eiji Nagamori ◽  
Takashi Matsuyama ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactate Dehydrogenase ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Bifidobacterium Longum ◽  
Yeast Cells ◽  
Efficient Production ◽  
Coding Region ◽  
A Genome ◽  
Dehydrogenase Gene

ABSTRACT We developed a metabolically engineered yeast which produces lactic acid efficiently. In this recombinant strain, the coding region for pyruvate decarboxylase 1 (PDC1) on chromosome XII is substituted for that of the l-lactate dehydrogenase gene (LDH) through homologous recombination. The expression of mRNA for the genome-integrated LDH is regulated under the control of the native PDC1 promoter, while PDC1 is completely disrupted. Using this method, we constructed a diploid yeast transformant, with each haploid genome having a single insertion of bovine LDH. Yeast cells expressing LDH were observed to convert glucose to both lactate (55.6 g/liter) and ethanol (16.9 g/liter), with up to 62.2% of the glucose being transformed into lactic acid under neutralizing conditions. This transgenic strain, which expresses bovine LDH under the control of the PDC1 promoter, also showed high lactic acid production (50.2 g/liter) under nonneutralizing conditions. The differences in lactic acid production were compared among four different recombinants expressing a heterologous LDH gene (i.e., either the bovine LDH gene or the Bifidobacterium longum LDH gene): two transgenic strains with 2μm plasmid-based vectors and two genome-integrated strains.

Immobilization of Rhizopus oryzae in a modified polyvinyl alcohol gel for L(+)-lactic acid production

2012 ◽  
Vol 63 (3) ◽  
pp. 957-964 ◽  
Author(s):  
Peng Wang ◽  
Zhen Chen ◽  
Juan Li ◽  
Li Wang ◽  
Guohong Gong ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Polyvinyl Alcohol ◽  
Acid Production ◽  
Rhizopus Oryzae ◽  
Lactic Acid Production

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 L (+)-lactic acid production by pellet-form Rhizopus oryzae NRRL 395 on biodiesel crude glycerol

2013 ◽  
Vol 12 (1) ◽  
pp. 92 ◽  
Author(s):  
Dan C Vodnar ◽  
Francisc V Dulf ◽  
Oana L Pop ◽  
Carmen Socaciu
Keyword(s):  
Lactic Acid ◽  
Acid Production ◽  
Crude Glycerol ◽  
Rhizopus Oryzae ◽  
Lactic Acid Production ◽  
Pellet Form
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