Limits...
Engineering of Nitrosomonas europaea to express Vitreoscilla hemoglobin enhances oxygen uptake and conversion of ammonia to nitrite.

Kunkel SA, Pagilla KR, Stark BC - AMB Express (2015)

Bottom Line: Vgb was maintained stably and appeared to be expressed in the transformants at VHb levels of about 0.75 nmol/g wet weight.Expression of VHb in the N. europaea transformants was correlated with an approximately 2 fold increase in oxygen uptake rate by whole cells at oxygen concentrations in the range of 75-100% saturation, but no change in oxygen uptake rate at oxygen concentrations below 25% saturation.VHb expression was also correlated with an increase of as much as about 30% in conversion of ammonia to nitrite by growing cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Illinois Institute of Technology, Chicago, IL, 60616, USA, skunkel@iit.edu.

ABSTRACT
Nitrosomonas europaea was transformed with a recombinant plasmid bearing the gene (vgb) encoding the hemoglobin (VHb) from the bacterium Vitreoscilla under control of the N. europaea amoC P1 promoter. Vgb was maintained stably and appeared to be expressed in the transformants at VHb levels of about 0.75 nmol/g wet weight. Expression of VHb in the N. europaea transformants was correlated with an approximately 2 fold increase in oxygen uptake rate by whole cells at oxygen concentrations in the range of 75-100% saturation, but no change in oxygen uptake rate at oxygen concentrations below 25% saturation. VHb expression was also correlated with an increase of as much as about 30% in conversion of ammonia to nitrite by growing cells. The results suggest that engineering of key aerobic wastewater bacteria to express bacterial hemoglobins may be a useful strategy to produce species with enhanced respiratory abilities.

No MeSH data available.


Related in: MedlinePlus

Ammonia to nitrite conversion as a function of cell mass (OD600 nm) for growing cultures of N. europaea[pSK2] and untransformed N. europaea. Each point is the average of 10 independent experiments; error bars indicate standard deviations.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4522006&req=5

Fig5: Ammonia to nitrite conversion as a function of cell mass (OD600 nm) for growing cultures of N. europaea[pSK2] and untransformed N. europaea. Each point is the average of 10 independent experiments; error bars indicate standard deviations.

Mentions: The transformant was also compared with the untransformed control strain regarding production of nitrite from ammonia during growth in ammonia medium (Fig. 5). These experiments were conducted from OD600 nm’s of about 0.008–0.104 (corresponding to growth during 5 days following inoculation). Earlier in the growth phase (OD600nm up to about 0.02, or about 2 days) the expression of VHb was correlated with an approximately 30% increase in nitrite conversion per unit of cell mass compared to the untransformed strain; the transformant’s advantage decreased gradually to only about 6% by OD600nm of about 0.10 (about 5 days of growth).Fig. 5


Engineering of Nitrosomonas europaea to express Vitreoscilla hemoglobin enhances oxygen uptake and conversion of ammonia to nitrite.

Kunkel SA, Pagilla KR, Stark BC - AMB Express (2015)

Ammonia to nitrite conversion as a function of cell mass (OD600 nm) for growing cultures of N. europaea[pSK2] and untransformed N. europaea. Each point is the average of 10 independent experiments; error bars indicate standard deviations.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4522006&req=5

Fig5: Ammonia to nitrite conversion as a function of cell mass (OD600 nm) for growing cultures of N. europaea[pSK2] and untransformed N. europaea. Each point is the average of 10 independent experiments; error bars indicate standard deviations.
Mentions: The transformant was also compared with the untransformed control strain regarding production of nitrite from ammonia during growth in ammonia medium (Fig. 5). These experiments were conducted from OD600 nm’s of about 0.008–0.104 (corresponding to growth during 5 days following inoculation). Earlier in the growth phase (OD600nm up to about 0.02, or about 2 days) the expression of VHb was correlated with an approximately 30% increase in nitrite conversion per unit of cell mass compared to the untransformed strain; the transformant’s advantage decreased gradually to only about 6% by OD600nm of about 0.10 (about 5 days of growth).Fig. 5

Bottom Line: Vgb was maintained stably and appeared to be expressed in the transformants at VHb levels of about 0.75 nmol/g wet weight.Expression of VHb in the N. europaea transformants was correlated with an approximately 2 fold increase in oxygen uptake rate by whole cells at oxygen concentrations in the range of 75-100% saturation, but no change in oxygen uptake rate at oxygen concentrations below 25% saturation.VHb expression was also correlated with an increase of as much as about 30% in conversion of ammonia to nitrite by growing cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Illinois Institute of Technology, Chicago, IL, 60616, USA, skunkel@iit.edu.

ABSTRACT
Nitrosomonas europaea was transformed with a recombinant plasmid bearing the gene (vgb) encoding the hemoglobin (VHb) from the bacterium Vitreoscilla under control of the N. europaea amoC P1 promoter. Vgb was maintained stably and appeared to be expressed in the transformants at VHb levels of about 0.75 nmol/g wet weight. Expression of VHb in the N. europaea transformants was correlated with an approximately 2 fold increase in oxygen uptake rate by whole cells at oxygen concentrations in the range of 75-100% saturation, but no change in oxygen uptake rate at oxygen concentrations below 25% saturation. VHb expression was also correlated with an increase of as much as about 30% in conversion of ammonia to nitrite by growing cells. The results suggest that engineering of key aerobic wastewater bacteria to express bacterial hemoglobins may be a useful strategy to produce species with enhanced respiratory abilities.

No MeSH data available.


Related in: MedlinePlus