Altered Superoxide Dismutase Activity by Carbohydrate Utilization in a Lactococcus lactis Strain

2014 ◽  
Vol 77 (7) ◽  
pp. 1161-1167 ◽  
Author(s):  
H. KIMOTO-NIRA ◽  
N. MORIYA ◽  
H. OHMORI ◽  
C. SUZUKI
Keyword(s):  
Superoxide Dismutase ◽  
Lactococcus Lactis ◽  
Dairy Products ◽  
Nadh Oxidase ◽  
Acid Fermentation ◽  
Sod Activity ◽  
Carbohydrate Utilization ◽  
Carbohydrate Source ◽  
Mixed Acid Fermentation ◽  
Mixed Acid

Reactive oxygen species, such as superoxide, can damage cellular components, such as proteins, lipids, and DNA. Superoxide dismutase (SOD) enzymes catalyze the conversion of superoxide anions to hydrogen peroxide and dioxygen. SOD is present in most lactococcal bacteria, which are commonly used as starters for manufacturing fermented dairy products and may have health benefits when taken orally. We assessed the effects of carbohydrate use on SOD activity in lactococci. In Lactococcus lactis ssp. lactis G50, the SOD activity of cells grown on lactose and galactose was higher than that on glucose; in Lactococcus lactis ssp. cremoris H61, SOD activity was independent of the type of carbohydrate used. We also investigated the activity of NADH oxidase, which is related to the production of superoxide in strains G50 and H61. Activity was highest in G50 cells grown on lactose, lower on galactose, and lowest on glucose, whereas activity in H61 cells did not differ with the carbohydrate source used. The SOD and NADH oxidase activities of strain G50 in three carbohydrates were linked. Strain G50 fermented lactose and galactose to lactate, acetate, formate, and ethanol (mixed-acid fermentation) and fermented glucose to mainly lactate (homolactic fermentation). Strain H61 fermented glucose, lactose, and galactose to mainly lactate (homolactic fermentation). In strain G50, when growth efficiency was reduced by adding a metabolic inhibitor to the growth medium, SOD activity was higher than in the control; however, the metabolism was homofermentative. Aerobic conditions, but not glucose-limited conditions, increased SOD activity, and mixed-acid fermentation occurred. We conclude that the effect of carbohydrate on SOD activity in lactococci is strain dependent and that the activity of commercial lactococci can be enhanced through carbohydrate selection for mixed-acid fermentation or by changing the energy distribution, thus enhancing the value of the starter and the resulting dairy products.

scholarly journals Cofactor Engineering: a Novel Approach to Metabolic Engineering in Lactococcus lactis by Controlled Expression of NADH Oxidase

1998 ◽  
Vol 180 (15) ◽  
pp. 3804-3808 ◽  
Author(s):  
Felix Lopez de Felipe ◽  
Michiel Kleerebezem ◽  
Willem M. de Vos ◽  
Jeroen Hugenholtz
Keyword(s):  
Lactococcus Lactis ◽  
Oxidase Activity ◽  
Nadh Oxidase ◽  
Metabolic Effects ◽  
Initial Growth ◽  
Acid Fermentation ◽  
Aerobic Conditions ◽  
Mixed Acid Fermentation ◽  
Mixed Acid ◽  
Nadh Oxidase Activity

ABSTRACT NADH oxidase-overproducing Lactococcus lactis strains were constructed by cloning the Streptococcus mutans nox-2gene, which encodes the H2O-forming NADH oxidase, on the plasmid vector pNZ8020 under the control of the L. lactis nisA promoter. This engineered system allowed a nisin-controlled 150-fold overproduction of NADH oxidase at pH 7.0, resulting in decreased NADH/NAD ratios under aerobic conditions. Deliberate variations on NADH oxidase activity provoked a shift from homolactic to mixed-acid fermentation during aerobic glucose catabolism. The magnitude of this shift was directly dependent on the level of NADH oxidase overproduced. At an initial growth pH of 6.0, smaller amounts of nisin were required to optimize NADH oxidase overproduction, but maximum NADH oxidase activity was twofold lower than that found at pH 7.0. Nonetheless at the highest induction levels, levels of pyruvate flux redistribution were almost identical at both initial pH values. Pyruvate was mostly converted to acetoin or diacetyl via α-acetolactate synthase instead of lactate and was not converted to acetate due to flux limitation through pyruvate dehydrogenase. The activity of the overproduced NADH oxidase could be increased with exogenously added flavin adenine dinucleotide. Under these conditions, lactate production was completely absent. Lactate dehydrogenase remained active under all conditions, indicating that the observed metabolic effects were only due to removal of the reduced cofactor. These results indicate that the observed shift from homolactic to mixed-acid fermentation under aerobic conditions is mainly modulated by the level of NADH oxidation resulting in low NADH/NAD+ratios in the cells.

scholarly journals Metabolic Profiling of Xylooligosaccharides by Lactobacilli

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2387
Author(s):  
Ilia Iliev ◽  
Tonka Vasileva ◽  
Veselin Bivolarski ◽  
Albena Momchilova ◽  
Iskra Ivanova
Keyword(s):  
Plasma Membranes ◽  
Meat Products ◽  
Lactobacillus Brevis ◽  
Degree Of Polymerization ◽  
Acid Fermentation ◽  
Carbohydrate Utilization ◽  
Beneficial Effects ◽  
Mixed Acid ◽  
Rat Liver Plasma Membranes ◽  
Different Types

Three lactic acid bacteria (LAB) strains identified as Lactobacillus plantarum, Lactobacillus brevis, and Lactobacillus sakei isolated from meat products were tested for their ability to utilize and grow on xylooligosaccharides (XOSs). The extent of carbohydrate utilization by the studied strains was analyzed by HPLC. All three strains showed preferences for the degree of polymerization (DP). The added oligosaccharides induced the LAB to form end-products of typical mixed-acid fermentation. The utilization of XOSs by the microorganisms requires the action of three important enzymes: β-xylosidase (EC 3.2.1.37) exo-oligoxylanase (EC 3.2.1.156) and α-L-arabinofuranosidase (EC 3.2.1.55). The presence of intracellular β-D-xylosidase in Lb. brevis, Lb. plantarum, and Lb. sakei suggest that XOSs might be the first imported into the cell by oligosaccharide transporters, followed by their degradation to xylose. The studies on the influence of XOS intake on the lipids of rat liver plasma membranes showed that oligosaccharides display various beneficial effects for the host organism, which are probably specific for each type of prebiotic used. The utilization of different types of oligosaccharides may help to explain the ability of Lactobacillus strains to compete with other bacteria in the ecosystem of the human gastrointestinal tract.

Enhanced hydrogen production in altered mixed acid fermentation of glucose by Enterobacter aerogenes

1997 ◽  
Vol 83 (4) ◽  
pp. 358-363 ◽  
Author(s):  
Mahyudin Abdul Rachman ◽  
Yoshinori Furutani ◽  
Yutaka Nakashimada ◽  
Toshihide Kakizono ◽  
Naomichi Nishio
Keyword(s):  
Hydrogen Production ◽  
Enterobacter Aerogenes ◽  
Acid Fermentation ◽  
Mixed Acid Fermentation ◽  
Mixed Acid

scholarly journals Aerobic Fermentation of d-Glucose by an Evolved Cytochrome Oxidase-Deficient Escherichia coli Strain

2008 ◽  
Vol 74 (24) ◽  
pp. 7561-7569 ◽  
Author(s):  
Vasiliy A. Portnoy ◽  
Markus J. Herrgård ◽  
Bernhard Ø. Palsson
Keyword(s):  
Escherichia Coli ◽  
Oxygen Uptake ◽  
Growth Conditions ◽  
Aerobic Growth ◽  
Acid Fermentation ◽  
Mixed Acid Fermentation ◽  
E Coli ◽  
Knockout Strain ◽  
Mixed Acid ◽  
Cytochrome Oxidases

ABSTRACT Fermentation of glucose to d-lactic acid under aerobic growth conditions by an evolved Escherichia coli mutant deficient in three terminal oxidases is reported in this work. Cytochrome oxidases (cydAB, cyoABCD, and cbdAB) were removed from the E. coli K12 MG1655 genome, resulting in the ECOM3 (E. coli cytochrome oxidase mutant) strain. Removal of cytochrome oxidases reduced the oxygen uptake rate of the knockout strain by nearly 85%. Moreover, the knockout strain was initially incapable of growing on M9 minimal medium. After the ECOM3 strain was subjected to adaptive evolution on glucose M9 medium for 60 days, a growth rate equivalent to that of anaerobic wild-type E. coli was achieved. Our findings demonstrate that three independently adaptively evolved ECOM3 populations acquired different phenotypes: one produced lactate as a sole fermentation product, while the other two strains exhibited a mixed-acid fermentation under oxic growth conditions with lactate remaining as the major product. The homofermenting strain showed a d-lactate yield of 0.8 g/g from glucose. Gene expression and in silico model-based analyses were employed to identify perturbed pathways and explain phenotypic behavior. Significant upregulation of ygiN and sodAB explains the remaining oxygen uptake that was observed in evolved ECOM3 strains. E. coli strains produced in this study showed the ability to produce lactate as a fermentation product from glucose and to undergo mixed-acid fermentation during aerobic growth.

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