Mixing control as a device to increase PHB production in batch fermentations with co-cultures of Lactobacillus delbrueckii and Ralstonia eutropha

2005 ◽  
Vol 40 (1) ◽  
pp. 257-264 ◽  
Author(s):  
V.S.R.K. Ganduri ◽  
S. Ghosh ◽  
P.R. Patnaik
Keyword(s):  
Ralstonia Eutropha ◽  
Lactobacillus Delbrueckii ◽  
Phb Production ◽  
Mixing Control

scholarly journals Ralstonia eutropha H16 Encodes Two and Possibly Three Intracellular Poly[d-(−)-3-Hydroxybutyrate] Depolymerase Genes

2003 ◽  
Vol 185 (13) ◽  
pp. 3788-3794 ◽  
Author(s):  
Gregory M. York ◽  
Joachim Lupberger ◽  
Jiamin Tian ◽  
Adam G. Lawrence ◽  
JoAnne Stubbe ◽  
...  
Keyword(s):  
Ralstonia Eutropha ◽  
Dry Weight ◽  
Complete Sequence ◽  
Inverse Pcr ◽  
Degenerate Primers ◽  
Phb Depolymerase ◽  
Phb Production ◽  
Ralstonia Metallidurans

ABSTRACT Intracellular poly[d-(−)-3-hydroxybutyrate] (PHB) depolymerases degrade PHB granules to oligomers and monomers of 3-hydroxybutyric acid. Recently an intracellular PHB depolymerase gene (phaZ1) from Ralstonia eutropha was identified. We now report identification of candidate PHB depolymerase genes from R. eutropha, namely, phaZ2 and phaZ3, and their characterization in vivo. phaZ1 was used to identify two candidate depolymerase genes in the genome of Ralstonia metallidurans. phaZ1 and these genes were then used to design degenerate primers. These primers and PCR methods on the R. eutropha genome were used to identify two new candidate depolymerase genes in R. eutropha: phaZ2 and phaZ3. Inverse PCR methods were used to obtain the complete sequence of phaZ3, and library screening was used to obtain the complete sequence of phaZ2. PhaZ1, PhaZ2, and PhaZ3 share ∼30% sequence identity. The function of PhaZ2 and PhaZ3 was examined by generating R. eutropha H16 deletion strains (ΔphaZ1, ΔphaZ2, ΔphaZ3, ΔphaZ1ΔphaZ2, ΔphaZ1ΔphaZ3, ΔphaZ2ΔphaZ3, and ΔphaZ1ΔphaZ2ΔphaZ3). These strains were analyzed for PHB production and utilization under two sets of conditions. When cells were grown in rich medium, PhaZ1 was sufficient to account for intracellular PHB degradation. When cells that had accumulated ∼80% (cell dry weight) PHB were subjected to PHB utilization conditions, PhaZ1 and PhaZ2 were sufficient to account for PHB degradation. PhaZ2 is thus suggested to be an intracellular depolymerase. The role of PhaZ3 remains to be established.

scholarly journals Whole-Genome Microarray and Gene Deletion Studies Reveal Regulation of the Polyhydroxyalkanoate Production Cycle by the Stringent Response in Ralstonia eutropha H16

2012 ◽  
Vol 78 (22) ◽  
pp. 8033-8044 ◽  
Author(s):  
Christopher J. Brigham ◽  
Daan R. Speth ◽  
ChoKyun Rha ◽  
Anthony J. Sinskey
Keyword(s):  
Gene Expression ◽  
Ralstonia Eutropha ◽  
Gene Expression Pattern ◽  
Stringent Response ◽  
Production Cycle ◽  
Chemical Induction ◽  
Physiological Basis ◽  
Content Type ◽  
Cellular Processes ◽  
Phb Production

ABSTRACTPoly(3-hydroxybutyrate) (PHB) production and mobilization inRalstonia eutrophaare well studied, but in only a few instances has PHB production been explored in relation to other cellular processes. We examined the global gene expression of wild-typeR. eutrophathroughout the PHB cycle: growth on fructose, PHB production using fructose following ammonium depletion, and PHB utilization in the absence of exogenous carbon after ammonium was resupplied. Our results confirm or lend support to previously reported results regarding the expression of PHB-related genes and enzymes. Additionally, genes for many different cellular processes, such as DNA replication, cell division, and translation, are selectively repressed during PHB production. In contrast, the expression levels of genes under the control of the alternative sigma factor σ54increase sharply during PHB production and are repressed again during PHB utilization. Global gene regulation during PHB production is strongly reminiscent of the gene expression pattern observed during the stringent response in other species. Furthermore, a ppGpp synthase deletion mutant did not show an accumulation of PHB, and the chemical induction of the stringent response withdl-norvaline caused an increased accumulation of PHB in the presence of ammonium. These results indicate that the stringent response is required for PHB accumulation inR. eutropha, helping to elucidate a thus-far-unknown physiological basis for this process.

scholarly journals Utilization of Noxious Weed Water Hyacinth Biomass as a Potential Feedstock for Biopolymers Production: A Novel Approach

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1704 ◽  
Author(s):  
Rijuta Ganesh Saratale ◽  
Si-Kyung Cho ◽  
Gajanan S. Ghodake ◽  
Han-Seung Shin ◽  
Ganesh Dattatraya Saratale ◽  
...  
Keyword(s):  
Water Hyacinth ◽  
Large Scale ◽  
Ralstonia Eutropha ◽  
Corn Steep Liquor ◽  
Enzymatic Saccharification ◽  
Reducing Sugar ◽  
Enzyme Hydrolysis ◽  
Ambient Conditions ◽  
Phb Production ◽  
Noxious Weed

This study aims to utilize a noxious weed water hyacinth biomass (WH) for polyhydroxybutyrate (PHB) production. Alkaline and peracetic acid pretreatment was employed for the hydrolysis of WH and consequently enzymatic saccharification to produce fermentable sugars for PHB production. The pretreatment competence was determined using various operational parameters. By applying ambient conditions, alkaline pretreatment gave higher lignin removal of 65.0%, with 80.8% hydrolysis yield, and on enzyme hydrolysis (40 FPU/g of dry WH), produced total reducing sugar of about 523 mg/g of WH. The resulted WH enzymatic hydolysates were evaluated for the production of PHB by Ralstonia eutropha (ATCC 17699). The WH hydrolysates cultivation was compared to synthetic hydrolysates that contain a similar carbon composition in terms of bacterial growth and PHB synthesis. The effects of various supplements to enhance PHB production were estimated. Supplementation of corn steep liquor (CSL) as a cheap nitrogen source with WH hydrolysates favored a higher amount of PHB synthesis (73%), PHB titer of 7.30 g/L and PHB yield of 0.429 g/g of reducing sugar. Finally, using standard analytical tools, the physical and thermal characteristics of the extracted PHB were evaluated. The findings revealed WH was a promising and technically feasible option for transforming biomass into sustainable biopolymer conversion on a large scale.

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