5 research outputs found
Revised sequence and annotation of the Rhodobacter sphaeroides 2.4.1 Genome
The DNA sequences of chromosomes I and II of Rhodobacter sphaeroides strain 2.4.1 have been revised, and the annotation of the entire genomic sequence, including both chromosomes and the five plasmids, has been updated. Errors in the originally published sequence have been corrected, and ∼11% of the coding regions in the original sequence have been affected by the revised annotation
Metabolism of Multiple Aromatic Compounds in Corn Stover Hydrolysate by <i>Rhodopseudomonas palustris</i>
Lignocellulosic
biomass hydrolysates hold great potential as a
feedstock for microbial biofuel production, due to their high concentration
of fermentable sugars. Present at lower concentrations are a suite
of aromatic compounds that can inhibit fermentation by biofuel-producing
microbes. We have developed a microbial-mediated strategy for removing
these aromatic compounds, using the purple nonsulfur bacterium Rhodopseudomonas palustris. When grown photoheterotrophically
in an anaerobic environment, R. palustris removes most of the aromatics from ammonia fiber expansion (AFEX)
treated corn stover hydrolysate (ACSH), while leaving the sugars mostly
intact. We show that R. palustris can
metabolize a host of aromatic substrates in ACSH that have either
been previously described as unable to support growth, such as methoxylated
aromatics, and those that have not yet been tested, such as aromatic
amides. Removing the aromatics from ACSH with R. palustris, allowed growth of a second microbe that could not grow in the untreated
ACSH. By using defined mutants, we show that most of these aromatic
compounds are metabolized by the benzoyl-CoA pathway. We also show
that loss of enzymes in the benzoyl-CoA pathway prevents total degradation
of the aromatics in the hydrolysate, and instead allows for biological
transformation of this suite of aromatics into selected aromatic compounds
potentially recoverable as an additional bioproduct
Pathways Involved in Reductant Distribution during Photobiological H2 Production by Rhodobacter sphaeroides â–¿ § â€
We used global transcript analyses and mutant studies to investigate the pathways that impact H2 production in the photosynthetic bacterium Rhodobacter sphaeroides. We found that H2 production capacity is related to the levels of expression of the nitrogenase and hydrogenase enzymes and the enzymes of the Calvin-Benson-Bassham pathway