scholarly journals Studies on poly-3-hydroxyoctanoate biosynthesis by a consortium of microorganisms

2016 ◽  
Vol 27 (1) ◽  
pp. 44-47 ◽  
Author(s):  
Mihaela Carmen Eremia ◽  
Irina Lupescu ◽  
Mariana Vladu ◽  
Maria Petrescu ◽  
Gabriela Savoiu ◽  
...  

Abstract Polyhydroxyalcanoates (PHAs) are specifically produced by a wide variety of bacteria, as an intracellular energy reserve in the form of homo- and copolymers of [R]-β-hydroxyalkanoic acids, depending on the C source used for microorganism growth, when the cells are grown under stressing conditions. In this paper we present microbiological accumulation of poly-3-hydroxyoctanoate (PHO) by using a consortium of bacterial strains, Pseudomonas putida and Bacillus subtilis, in a rate of 3:1, grown on a fermentation medium based on sodium octanoate as the sole carbon source. The experiments performed in the above mentioned conditions led to the following results: from 18.70 g sodium octanoate (7.72 g/L in the fermentation medium) used up during the bioprocess, 3.93-3.96 g/L dry bacterial biomass and 1.834 - 1.884 g/L PHA, containing 85.83 - 86.8% PHO, were obtained.

2010 ◽  
Vol 76 (24) ◽  
pp. 7972-7980 ◽  
Author(s):  
Petra R. A. Kohler ◽  
Jasmine Y. Zheng ◽  
Elke Schoffers ◽  
Silvia Rossbach

ABSTRACT The nitrogen-fixing symbiont of alfalfa, Sinorhizobium meliloti, is able to use myo-inositol as the sole carbon source. Putative inositol catabolism genes (iolA and iolRCDEB) have been identified in the S. meliloti genome based on their similarities with the Bacillus subtilis iol genes. In this study, functional mutational analysis revealed that the iolA and iolCDEB genes are required for growth not only with the myo-isomer but also for growth with scyllo- and d-chiro-inositol as the sole carbon source. An additional, hypothetical dehydrogenase of the IdhA/MocA/GFO family encoded by the smc01163 gene was found to be essential for growth with scyllo-inositol, whereas the idhA-encoded myo-inositol dehydrogenase was responsible for the oxidation of d-chiro-inositol. The putative regulatory iolR gene, located upstream of iolCDEB, encodes a repressor of the iol genes, negatively regulating the activity of the myo- and the scyllo-inositol dehydrogenases. Mutants with insertions in the iolA, smc01163, and individual iolRCDE genes could not compete against the wild type in a nodule occupancy assay on alfalfa plants. Thus, a functional inositol catabolic pathway and its proper regulation are important nutritional or signaling factors in the S. meliloti-alfalfa symbiosis.


2007 ◽  
Vol 73 (9) ◽  
pp. 3105-3108 ◽  
Author(s):  
Giomar Rivera-Cancel ◽  
Daniela Bocioaga ◽  
Anthony G. Hay

ABSTRACT Pseudomonas putida DTB grew aerobically with N,N-diethyl-m-toluamide (DEET) as a sole carbon source, initially breaking it down into 3-methylbenzoate and diethylamine. The former was further metabolized via 3-methylcatechol and meta ring cleavage. A gene from DTB, dthA, was heterologously expressed and shown to encode the ability to hydrolyze DEET into 3-methylbenzoate and diethylamine.


2019 ◽  
Author(s):  
Mitchell G. Thompson ◽  
Luis E. Valencia ◽  
Jacquelyn M. Blake-Hedges ◽  
Pablo Cruz-Morales ◽  
Alexandria E. Velasquez ◽  
...  

ABSTRACTPseudomonas putida is a promising bacterial chassis for metabolic engineering given its ability to metabolize a wide array of carbon sources, especially aromatic compounds derived from lignin. However, this omnivorous metabolism can also be a hindrance when it can naturally metabolize products produced from engineered pathways. Herein we show that P. putida is able to use valerolactam as a sole carbon source, as well as degrade caprolactam. Lactams represent important nylon precursors, and are produced in quantities exceeding one million tons per year[1]. To better understand this metabolism we use a combination of Random Barcode Transposon Sequencing (RB-TnSeq) and shotgun proteomics to identify the oplBA locus as the likely responsible amide hydrolase that initiates valerolactam catabolism. Deletion of the oplBA genes prevented P. putida from growing on valerolactam, prevented the degradation of valerolactam in rich media, and dramatically reduced caprolactam degradation under the same conditions. Deletion of oplBA, as well as pathways that compete for precursors L-lysine or 5-aminovalerate, increased the titer of valerolactam from undetectable after 48 hours of production to ~90 mg/L. This work may serve as a template to rapidly eliminate undesirable metabolism in non-model hosts in future metabolic engineering efforts.


2002 ◽  
Vol 57 (3-4) ◽  
pp. 356-360 ◽  
Author(s):  
Borjana K. Tuleva ◽  
George R. Ivanov ◽  
Nelly E. Christova

Observation of both tensio-active and emulsifying activities indicated that biosurfactants were produced by the newly isolated and promising strain Pseudomonas putida 21BN. The biosurfactants were identified as rhamnolipids, the amphiphilic surface-active glycolipids usually secreted by Pseudomonas spp. Their production was observed when the strain was grown on soluble substrates, such as glucose or on poorly soluble substrates, such as hexadecane, reaching values of 1.2 g l-1. When grown on hexadecane as the sole carbon source the biosurfactant lowered the surface tension of the medium to 29 mN m-1 and formed stable and compact emulsions with emulsifying activity of 69%


1999 ◽  
Vol 181 (12) ◽  
pp. 3837-3841 ◽  
Author(s):  
Min Huang ◽  
Fred Bernd Oppermann-Sanio ◽  
Alexander Steinbüchel

ABSTRACT A recent study indicated that Bacillus subtiliscatabolizes acetoin by enzymes encoded by the acu gene cluster (F. J. Grundy, D. A. Waters, T. Y. Takova, and T. M. Henkin, Mol. Microbiol. 10:259–271, 1993) that are completely different from those in the multicomponent acetoin dehydrogenase enzyme system (AoDH ES) encoded by aco gene clusters found before in all other bacteria capable of utilizing acetoin as the sole carbon source for growth. By hybridization with a DNA probe covering acoA and acoB of the AoDH ES from Clostridium magnum, genomic fragments from B. subtilis harboring acoA, acoB,acoC, acoL, and acoR homologous genes were identified, and some of them were functionally expressed inE. coli. Furthermore, acoA was inactivated inB. subtilis by disruptive mutagenesis; these mutants were impaired to express PPi-dependent AoDH E1 activity to remove acetoin from the medium and to grow with acetoin as the carbon source. Therefore, acetoin is catabolized in B. subtilis by the same mechanism as all other bacteria investigated so far, leaving the function of the previously described acu genes obscure.


Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7122
Author(s):  
Shuangfeng Cai ◽  
Yaran Wu ◽  
Yanan Li ◽  
Shuying Yang ◽  
Zhi Liu ◽  
...  

The chlorophyll ethanol-extracted silkworm excrement was hardly biologically reused or fermented by most microorganisms. However, partial extremely environmental halophiles were reported to be able to utilize a variety of inexpensive carbon sources to accumulate polyhydroxyalkanoates. In this study, by using the nile red staining and gas chromatography assays, two endogenous haloarchaea strains: Haloarcula hispanica A85 and Natrinema altunense A112 of silkworm excrement were shown to accumulate poly(3-hydroxybutyrate) up to 0.23 g/L and 0.08 g/L, respectively, when using the silkworm excrement as the sole carbon source. The PHA production of two haloarchaea showed no significant decreases in the silkworm excrement medium without being sterilized compared to that of the sterilized medium. Meanwhile, the CFU experiments revealed that there were more than 60% target PHAs producing haloarchaea cells at the time of the highest PHAs production, and the addition of 0.5% glucose into the open fermentation medium can largely increase both the ratio of target haloarchaea cells (to nearly 100%) and the production of PHAs. In conclusion, our study demonstrated the feasibility of using endogenous haloarchaea to utilize waste silkworm excrement, effectively. The introduce of halophiles could provide a potential way for open fermentation to further lower the cost of the production of PHAs.


2019 ◽  
Vol 7 (4.14) ◽  
pp. 7
Author(s):  
P Paulraj ◽  
S Periyavedi ◽  
K Sajna ◽  
P T Mohamed Javad ◽  
P Sajeesh ◽  
...  

Plastics are synthetic polymers that changed our daily life due to their applications. But it’s increasing environmental problems had made the researchers find the alternative way such as usage of biodegradable plastics like Polyhydroxyalkanoates (PHA) which has similar properties to the conventional plastic. In this research production and characterization of PHAs using sugar industry wastes as a sole carbon source was carried in order to reduce the cost of production of PHA. Isolation of heterotrophic native micro flora from soil sample contaminated with sugar effluent for amylolytic and cellulolytic activity with PHA production potentials was carried out.  Suitable conditions for PHA accumulation were optimized with 1X and 2X MSM with sugar effluent as a sole carbon source and bacteriostatic antibiotics as an inducer using bi-phasic system. A total of 14 different heterotrophic native bacterial strains were isolated, among them, 4 isolates showed starch hydrolytic property, 7 isolates showed cellulolytic activity and 7 were PHA producers. The strain with the highest PHA accumulation (99.99µg/mL of culture) in 2X MSM with sugar effluent within 6 hours was considered as a potential strain (53% of PHB CWD). The isolate was confirmed as Chryseobacterium Sp. using 16S rRNA sequencing. 


2011 ◽  
Vol 8 (4) ◽  
pp. 1582-1587 ◽  
Author(s):  
M. Mohsen Nourouzi ◽  
T. G. Chuah ◽  
Thomas S. Y. Choong ◽  
C. J. Lim

Mixed bacteria from oil palm plantation soil (OPS) were isolated to investigate their ability to utilize glyphosate as carbon source. Results showed that approximately all of the glyphosate was converted to aminomethyl-phosphonic acid (AMPA) (99.5%). It is worthy to note that mixed bacteria were able to degrade only 2% of AMPA to further metabolites. Two bacterial strainsi.e. Stenotrophomonas maltophiliaandProvidencia alcalifacienswere obtained from enrichment culture. Bacterial isolates were cultured individually on glyphosate as a sole carbon source. It was observed that both isolates were able to convert glyphosate to AMPA.


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