Coenzyme regeneration catalyzed by NADH oxidase from Lactococcus lactis

2014 ◽  
Vol 88 ◽  
pp. 12-18 ◽  
Author(s):  
Martina Sudar ◽  
Zvjezdana Findrik ◽  
Marija Vuković Domanovac ◽  
Đurđa Vasić-Rački
Keyword(s):  
Lactococcus Lactis ◽  
Nadh Oxidase ◽  
Coenzyme Regeneration

Hydrogen peroxide-producing NADH oxidase (nox-1) from Lactococcus lactis

2004 ◽  
Vol 15 (18) ◽  
pp. 2939-2944 ◽  
Author(s):  
Rongrong Jiang ◽  
Andreas S. Bommarius
Keyword(s):  
Hydrogen Peroxide ◽  
Lactococcus Lactis ◽  
Nadh Oxidase

scholarly journals High-Level Acetaldehyde Production in Lactococcus lactis by Metabolic Engineering

2005 ◽  
Vol 71 (2) ◽  
pp. 1109-1113 ◽  
Author(s):  
Roger S. Bongers ◽  
Marcel H. N. Hoefnagel ◽  
Michiel Kleerebezem
Keyword(s):  
Metabolic Engineering ◽  
Lactococcus Lactis ◽  
Zymomonas Mobilis ◽  
Nadh Oxidase ◽  
Pyruvate Decarboxylase ◽  
Resting Cells ◽  
Anaerobic Conditions ◽  
High Level ◽  
Acetaldehyde Production ◽  
Combined Overexpression

ABSTRACT Efficient conversion of glucose to acetaldehyde is achieved by nisin-controlled overexpression of Zymomonas mobilis pyruvate decarboxylase (pdc) and Lactococcus lactis NADH oxidase (nox) in L. lactis. In resting cells, almost 50% of the glucose consumed could be redirected towards acetaldehyde by combined overexpression of pdc and nox under anaerobic conditions.

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 Simultaneous hydrolysis and fermentation of defatted rice bran and defatted soybean meal for nisin production with engineered Lactococcus lactis

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6385-6403
Author(s):  
Jiaheng Liu ◽  
Xiangyu He ◽  
Yuhui Du ◽  
Itsanun Wiwatanaratanabutr ◽  
Guangrong Zhao ◽  
...  
Keyword(s):  
Lactococcus Lactis ◽  
Rice Bran ◽  
Soybean Meal ◽  
Nadh Oxidase ◽  
Nitrogen Sources ◽  
Nisin Production ◽  
Carbon And Nitrogen ◽  
Defatted Soybean Meal ◽  
Commercial Media ◽  
Defatted Rice Bran

This work aimed to study the potential of defatted rice bran (DRB) and defatted soybean meal (DSM) as carbon and nitrogen sources for Lactococcus lactis growth and nisin production. First, a maximum nisin yield of 3630 IU/mL was achieved using 40% DRB hydrolysates and 30% DSM hydrolysates, which was 1.13 times greater than that found in commercial media. Second, to simplify the operation and shorten the length of the entire process, the processes of combined hydrolysis of DRB-DSM followed by fermentation, and simultaneous hydrolysis and fermentation of DRB-DSM were developed. Neutral proteinase enhanced the saccharification of DRB by cellulase and α-amylase. Furthermore, the strategy of NADH oxidase expression and hemin addition was innovatively proposed to overcome the oxygen stress in a simultaneous hydrolysis and fermentation process, which could alleviate the lag period following inoculation of L. lactis and result in a 77.3% increase in nisin titer.

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 Oxidative Stress at High Temperatures in Lactococcus lactis Due to an Insufficient Supply of Riboflavin

2013 ◽  
Vol 79 (19) ◽  
pp. 6140-6147 ◽  
Author(s):  
Jun Chen ◽  
Jing Shen ◽  
Christian Solem ◽  
Peter Ruhdal Jensen
Keyword(s):  
Oxidative Stress ◽  
Dissolved Oxygen ◽  
Lactococcus Lactis ◽  
High Temperatures ◽  
Pyruvate Dehydrogenase ◽  
Fluorescent Protein ◽  
Nadh Oxidase ◽  
Defined Medium ◽  
Content Type ◽  
Green Fluorescent

ABSTRACTLactococcus lactisMG1363 was found to be unable to grow at temperatures above 37°C in a defined medium without riboflavin, and the cause was identified to be dissolved oxygen introduced during preparation of the medium. At 30°C, growth was unaffected by dissolved oxygen and oxygen was consumed quickly. Raising the temperature to 37°C resulted in severe growth inhibition and only slow removal of dissolved oxygen. Under these conditions, an abnormally low intracellular ratio of [ATP] to [ADP] (1.4) was found (normally around 5), which indicates that the cells are energy limited. By adding riboflavin to the medium, it was possible to improve growth and oxygen consumption at 37°C, and this also normalized the [ATP]-to-[ADP] ratio. A codon-optimized redox-sensitive green fluorescent protein (GFP) was introduced intoL. lactisand revealed a more oxidized cytoplasm at 37°C than at 30°C. These results indicate thatL. lactissuffers from heat-induced oxidative stress at increased temperatures. A decrease in intracellular flavin adenine dinucleotide (FAD), which is derived from riboflavin, was observed with increasing growth temperature, but the presence of riboflavin made the decrease smaller. The drop was accompanied by a decrease in NADH oxidase and pyruvate dehydrogenase activities, both of which depend on FAD as a cofactor. By overexpressing the riboflavin transporter, it was possible to improve FAD biosynthesis, which resulted in increased NADH oxidase and pyruvate dehydrogenase activities and improved fitness at high temperatures in the presence of oxygen.

scholarly journals Formation and Conversion of Oxygen Metabolites by Lactococcus lactis subsp. lactis ATCC 19435 under Different Growth Conditions

2002 ◽  
Vol 68 (9) ◽  
pp. 4350-4356 ◽  
Author(s):  
Ed W. J. van Niel ◽  
Karin Hofvendahl ◽  
Bärbel Hahn-Hägerdal
Keyword(s):  
Growth Rate ◽  
Lactococcus Lactis ◽  
Nadh Oxidase ◽  
Growth Conditions ◽  
Lag Phase ◽  
Specific Rate ◽  
Strain Atcc ◽  
Potential Alternative ◽  
Reducing Activity ◽  
Casamino Acids

ABSTRACT A semidefined medium based on Casamino Acids allowed Lactococcus lactis ATCC 19435 to grow in the presence of oxygen at a slow rate (0.015 h−1). Accumulation of H2O2 in the culture prevented a higher growth rate. Addition of asparagine to the medium increased the growth rate, whereby H2O2 accumulated only temporarily during the lag phase. H2O2 is an inhibitor for several glycolytic enzymes, glyceraldehyde-3-phosphate dehydrogenase being the most sensitive. Strain ATCC 19435 contained NADH oxidase (maximum specific rate under aerobic conditions, 426 nmol of NADH min−1 mg of protein−1), which reduced oxygen to water, whereby superoxide was formed as a by-product. H2O2 originated from the dismutation of superoxide by superoxide dismutase. Although H2O2 was rapidly destroyed under high metabolic fluxes, neither NADH peroxidase nor any other enzymatic H2O2-reducing activity was detected. However, pyruvate, the end product of glycolysis, reacted nonenzymatically and rapidly with H2O2 and hence was a potential alternative for scavenging of this oxygen metabolite intracellularly. Indeed, intracellular concentrations of up to 93 mM pyruvate were detected in aerobic cultures growing at high rates. It is hypothesized that self-generated pyruvate may serve to protect L. lactis strain ATCC 19435 from H2O2.

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