ABSTRACT A recombinant E. coli strain (K24K) was constructed and evaluated for poly(3-hydroxybutyrate) (PHB) production from whey corn steep liquor as main carbon nitrogen sources. This bears the pha biosynthetic genes Azotobacter sp. FA8 expressed a T5 promoter under control of lactose operator. K24K does not produce repressor, ensuring constitutive expression involved in transport utilization. PHB efficiently produced by grown aerobically fed-batch cultures laboratory scale bioreactor on...

Bioreactor cultures of Escherichia coli recombinants carrying phaBAC and phaP Azotobacter sp. FA8 grown on glycerol under low-agitation conditions accumulated more poly(3-hydroxybutyrate) (PHB) ethanol than at high agitation, while in glucose cultures, low agitation led to a decrease PHB formation. Cells produced smaller amounts acids from glucose. Glycerol batch stirred 125 rpm accumulated, 24 h, 30.1% (wt/wt) with relative molecular mass 1.9 MDa, close that obtained using

To study phosphate solubilization in Penicillium purpurogenum as function of medium pH, and carbon nitrogen concentrations.Tricalcium (CP) efficiency P. was evaluated at acid or alkaline pH using different C N sources. Glucose- (NH(4) )(2) SO(4) -based media showed the highest P values followed by fructose. solubilizing ability higher cultures grown 6·5 than 8·5. Organic acids were detected both neutral media, but relative percentages each organic differed. Highest release coincided with...

The genus Coprothermobacter (initially named Thermobacteroides) is currently placed within the phylum Firmicutes. Early 16S rRNA gene based phylogenetic studies pointed out great differences between and other members of Firmicutes, revealing that it constitutes a new deep branching lineage. Over years, several on whole genome sequences have indicated very distant phylogenetically to all bacteria, supporting its placement in distinct deeply rooted novel phylum. In view this, we propose...

ABSTRACT We assessed the effects of different arcA mutations on poly(3-hydroxybutyrate) (PHB) synthesis in recombinant Escherichia coli strains carrying pha genes from Azotobacter sp. strain FA8. The used were an internal deletion and arcA2 allele, a leaky mutation for some characteristics Arc phenotype which confers high respiratory capacity. PHB was not detected wild-type shaken flask cultures under low-oxygen conditions, while ArcA mutants gave rise to polymer accumulation up 24% their...

ABSTRACT Polyhydroxyalkanoates (PHAs) are accumulated as intracellular granules by many bacteria under unfavorable conditions, enhancing their fitness and stress resistance. Poly(3-hydroxybutyrate) (PHB) is the most widespread best-known PHA. Apart from genes that catalyze polymer biosynthesis, natural PHA producers have several for proteins involved in granule formation and/or with regulatory functions, such phasins, been shown to affect synthesis. This study evaluates effect of PhaP, a...

ABSTRACT Phasins (PhaP) are proteins normally associated with granules of poly(3-hydroxybutyrate) (PHB), a biodegradable polymer accumulated by many bacteria as reserve molecule. These enhance growth and production in natural recombinant PHB producers. It has been shown that the causes stress Escherichia coli , revealed an increase concentrations several heat proteins. In this work, quantitative reverse transcription (qRT)-PCR analysis was used to study effect accumulation, PhaP from...

ArcA is a global regulator that switches on the expression of fermentation genes and represses aerobic pathways when Escherichia coli enters low oxygen growth conditions. The metabolic profile E. CT1062 (DeltaarcA)and CT1061 (arcA2) grown in microaerobiosis with glycerol as carbon source were determined compared K1060, arcA+ parent strain. Both arcA mutants achieved higher biomass yields than wild-type production acetate, formate, lactate, pyruvate, succinate ethanol supernatants cultures...

Aims: Analysis of the physiology and metabolism Escherichia coli arcA creC mutants expressing a bifunctional alcohol‐acetaldehyde dehydrogenase from Leuconostoc mesenteroides growing on glycerol under oxygen‐restricted conditions. The effect an ldhA mutation different growth medium modifications was also assessed. Methods Results: Expression adhE in E. CT1061 [arcA creC(Con)] resulted 1·4‐fold enhancement ethanol synthesis. Significant amounts lactate were produced during micro‐oxic cultures...

Summary Phasins are proteins associated to intracellular polyhydroxyalkanoate granules that affect polymer accumulation and the number size of granules. Previous work demonstrated a phasin from A zotobacter sp FA ‐8 ( PhaP Az ) had an unexpected growth‐promoting stress‐protecting effect in E scherichia coli , suggesting it could have chaperone‐like activities. In this work, vitro vivo experiments were performed order investigate possibility. was shown prevent thermal aggregation model...

arcA codes for a central regulator in Escherichia coli that responds to redox conditions of growth. Mutations this gene, originally named dye, confer sensitivity toluidine blue and other dyes. However, the molecular basis dye-sensitive phenotype has not been elucidated. In work, we show redirects electrons O2 causes an increase generation reactive species (ROS). We also demonstrate synthesis poly (3-hydroxybutyrate) suppresses Dye E. recombinants, as capacity synthesize polymer reduces blue,...

Abstract Background Guanine crystals are organic biogenic found in many organisms. Due to their exceptionally high refractive index, they contribute structural color and responsible for the reflective effect skin visual organs animals such as fish, reptiles, spiders. Occurrence of these has been known years, have also observed eukaryotic microorganisms, but not prokaryotes. Results In this work, we report discovery extracellular formed by bacteria reveal that composed guanine monohydrate....

ABSTRACT The microbial production of biofuels and other added-value chemicals is often limited by the intrinsic toxicity these compounds. phasin PhaP from soil bacterium Azotobacter sp. strain FA8 a polyhydroxyalkanoate granule-associated protein that protects recombinant Escherichia coli against several kinds stress. enhances growth poly(3-hydroxybutyrate) synthesis in polymer-producing strains reduces formation inclusion bodies during overproduction heterologous proteins. In this work,...

Genes responsible for the synthesis of poly(3-hydroxybutyrate) (PHB) in Azotobacter sp. FA8 were cloned and analyzed. A PHB polymerase gene (phbC) was found downstream from genes coding beta-ketothiolase (phbA) acetoacetyl-coenzyme reductase (phbB). synthase mutant obtained by inactivation used genetic studies. The phbC this strain introduced into Ralstonia eutropha PHB-4 (phbC-negative mutant), recombinant accumulated when either glucose or octanoate as a source carbon, indicating that...