Optimum Condition for Polyhydroxyalkanoate Production from Crude Glycerol by Bacillus sp. Isolated from Lipid-Containing Wastewater (original) (raw)
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Animal fat and glycerol bioconversion to polyhydroxyalkanoate by produced water bacteria
e-Polymers
Oil reservoirs contain large amounts of hydrocarbon rich produced water, trapped in underground channels. Focus of this study was isolation of PHA producers from produced water concomitant with optimization of production using animal fat and glycerol as carbon source. Bacterial strains were identified as Bacillus subtilis (PWA), Pseudomonas aeruginosa (PWC), Bacillus tequilensis (PWF), and Bacillus safensis (PWG) based on 16S rRNA gene sequencing. Similar amounts of PHA were obtained using animal fat and glycerol in comparison to glucose. After 24 h, high PHA production on glycerol and animal fat was shown by strain PWC (5.2 g/ L, 6.9 g/ L) and strain PWF (12.4 g/ L, 14.2 g/ L) among all test strains. FTIR analysis of PHA showed 3-hydroxybutyrate units. The capability to produce PHA in the strains was corroborated by PhaC synthase gene sequencing. Focus of future studies can be the use of lipids and glycerol on industrial scale.
Substrate versatility of polyhydroxyalkanoate producing glycerol grown bacterial enrichment culture
Water research, 2014
Waste-based polyhydroxyalkanoate (PHA) production by bacterial enrichments generally follows a three step strategy in which first the wastewater is converted into a volatile fatty acid rich stream that is subsequently used as substrate in a selector and biopolymer production units. In this work, a bacterial community with high biopolymer production capacity was enriched using glycerol, a non-fermented substrate. The substrate versatility and PHA production capacity of this community was studied using glucose, lactate, acetate and xylitol as substrate. Except for xylitol, very high PHA producing capacities were obtained. The PHA accumulation was comparable or even higher than with glycerol as substrate. This is the first study that established a high PHA content (≈70 wt%) with glucose as substrate in a microbial enrichment culture. The results presented in this study support the development of replacing pure culture based PHA production by bacterial enrichment cultures. A process whe...
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences, 2015
Municipal sewage triggers a stress prone environment to accumulate polyhydroxyalkanoates (PHAs) in the cytosol of bacteria. In view of that, different Bacillus species were isolated from municipal sewage and screened for evaluating their efficacy of PHA production. Growth parameters such as temperature, pH, glucose concentration and carbon nitrogen combinations were optimized with respect to higher biomass production as it is analogous to PHA accumulation. Under optimized conditions, the Bacillus species produced 3.09 g/L of PHAs which was estimated as a higher yield in comparison to other similar strains. Fourier transform infrared spectroscopic analysis of the extracted polyhydroxybutyrate confirmed the distinct peak corresponding to C=O group, whereas proton nuclear magnetic resonance (1 H NMR) and differential scanning colorimetric analysis exhibited detailed insight of its chemical structure and properties by reflecting monomeric unit. The high yielding bacterial isolate was identified by 16S rDNA sequencing and the sequence was confirmed as Bacillus subtilis with an accession no. KP172548 after submission to NCBI data base. The potential bacterium may be further exploited for cost effective and mass scale production of biopolymer.
Production and Optimization of Polyhydroxyalkanoate from Oleaginous Bacteria Bacillus Sp. ISTC1
Research & Reviews: Journal of Microbiology and Biotechnology, 2016
The present effort involved isolation and screening of bacterial strain Bacillus sp. ISTC1 for production of PHA and optimization of selected process parameters for enhanced production of PHA and biomass. Screening of selected bacterial strain for PHA production was based on Nile red staining, fluorescence microscopic visualization, spectrofluorometric measurement of Nile red fluorescence of the bacterial culture having 0.5% (w/v) glucose as carbon source. The presence of 3-hydroxyvalerate revealed by GC–MS served as a confirmatory analysis of PHA accumulation. Detection of characteristic functional group by FT-IR further confirmed the production of PHA by the bacterium. Response Surface Methodology (RSM) was used for optimization of pH, time duration and carbon source concentrations for an increased PHA production. On equating the optimized condition with the pre-optimized one, there was almost a 60% increase in the production of PHA. Therefore the finding thus established the production of PHA by Bacillus sp. ISTC1.
Biomass
The production of polyhydroxyalkanoates (PHAs) by Bacillus megaterium using industrial residues, crude glycerol from biodiesel synthesis and rice hull hydrolysate (RHH), as low-cost carbon sources was investigated. The experiments were conducted by shaking flasks at 30 °C and 180 rpm up to 72 h. The extraction of PHA was carried out using sodium hypochlorite to make its recovery more environmentally friendly by avoiding organic solvents (chloroform). The yields of PHA varied depending on the extraction method. A total of 33.3% (w·w−1) (mixing chloroform: sodium hypochlorite) and 52.5% (w·w−1) (sodium hypochlorite only) were obtained using glycerol and glucose as a carbon source, respectively. Preliminary experiments using RHH as a carbon source Indicated a yield of PHA of 11% (w·w−1) (chloroform). The PHA produced had thermal properties, such as transition temperature, similar to the commercial polyhydroxybutyrate (PHB).
Annals of Microbiology, 2014
Increasing global concerns over plastic waste disposal and environmental awareness has already highlighted Polyhydroxyalkanoates (PHA's) as an increasingly attractive bioplastic option. In this regard, the present investigation aims to highlight the production of polyhydroxyalkanoate by Pseudomonas aeruginosa BPC2 (GeneBank entry: JQ866912) using a glycerol by-product as an inexpensive carbon source. The glycerol by-product was generated via the production of biodiesel from kitchen chimney dump lard (KCDL). The strain was also cultured in media comprising other carbon sources like glycerol (commercial), sugar cane molasses and glucose for comparative PHA yield. An appreciable PHA accumulation up to 22.5 % of cell dry weight was found when the bacterium was cultured in media comprised of glycerol by-product. The extracted bacterial biopolymer was further characterized by FTIR, GC-MS, GPC and TGA. The experimental results of the study warrant the feasibility of bacterial biopolymer production using glycerol byproduct as an inexpensive carbon source.
Biocatalysis and Agricultural Biotechnology, 2019
Burkholderia glumae MA13 was isolated from soil samples of Atlantic rain forest ecosystem as a new bacterial strain for polyhydroxyalkanoate (PHA) production from crude glycerol as sole carbon source. Among 107 glycerol consuming bacterial isolates, B. glumae MA13 was cultivated in shake flask experiments in order to verify its PHA production capability from crude glycerol besides waste cooking oil and sugarcane molasses free of pretreatment, showing intracellular poly(3-hydroxybutyrate) [P(3HB)] accumulation values of 51.3, 51.4 and 49% of cell dry weight (CDW), respectively. The addition of propionic or hexanoic acids to the media containing crude glycerol resulted in the copolymers poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] comprised of up to 32.1 mol% of 3HV monomer or poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] with a maximum of 0.3 mol% of 3HHx, respectively. Fed-batch cultivation performed in a 10 L-scale bioreactor showed a maximum P(3HB-co-3HV) production of 9.9 g/L, which was 65.1% of total biomass and consisted of 21.8 mol% of 3HV monomer, with a maximum volumetric productivity of 0.22 g/(L h). The 3HV conversion yield achieved 1.04 g/g after 48 h cultivation, which was 76.7% of the maximum theoretical yield. B. glumae MA13 has showed to be an adapted bacterial strain to the synthesis of bioplastics from biofuel byproducts, and so from here it has been revealed as a promising PHA producer for an associated production set which has been considered as a prominent and ecologically friendly alternative to petrochemical plastics and fuels.
2017
Production of bioplastic has recently attracted great interest as an environmentally friendly alternative to petrochemical plastics. The present study aimed at production of polyhydroxyalkanoates (PHAs), a biodegradable thermoplastic, from agro-industrial wastes by potent bacterial isolates. Ninety-six isolates were obtained from different localities in Egypt and assayed for qualitative and quantitative production of PHA using sugarcane molasses. Bacterial isolate AZU-A2 showed the highest production of PHA. This strain was identified as Bacillus flexus strain AZU-A2 by 16S rRNA gene sequence and biochemical characterization. Physiological and nutritional factors affecting PHA production were optimized in batch fermentations. Agitation rate, supplementation of acetic acid as an auxiliary carbon source, and ammonium chloride as nitrogen source were critical factors affecting fermentation of PHA production. Maximum production of 3.97 g/L PHA with recovery yield of 88.0 (%, w/w) was ac...
International Journal of Polymer Science, 2016
Polyhydroxyalkanoates (PHAs) are biodegradable and biocompatible plastics. They are synthesized by a wide variety of microorganisms (i.e., fungi and bacteria) and some organisms such as plants, which share characteristics with petrochemical-based plastics. The most recent studies focus on finding inexpensive substrates and extraction strategies that allow reducing product costs, thus moving into a widespread market, the market for petroleum-based plastics. In this study, the production of polyhydroxybutyrate (PHB) was evaluated using the native strains, Bacillus megaterium, Bacillus sp., and Lactococcus lactis, and glycerol reagent grade (GRG), residual glycerol (RGSB) byproduct of biodiesel from palm oil, Jatropha oil, castor oil, waste frying oils, and whey as substrates. Different bacteria-substrate systems were evaluated thrice on a laboratory scale under different conditions of temperature, pH, and substrate concentration, employing 50 mL of broth in 250 mL. The bacterial growth was tested in all systems; however, the B. megaterium GRG system generated the highest accumulation of PHA. The previous approach was allowed to propose a statistical design optimization with RGSB (i.e., RGSB, 15 g/L, pH 7.0, and 25 ∘ C). This system reached 2.80 g/L of PHB yield and was the optimal condition tested; however, the optimal biomass 5.42 g/L occurs at pH 9.0 and 25 ∘ C, with a substrate concentration of 22 g/L.
Polyhydroxyalkanoates are recently found to be suitable alternative to conventional petrochemical plastics because of their similar material properties and complete degradability. These are microbial polyesters synthesized by several bacteria intracellularly as source of carbon and energy. In the present study, the efficient PHA-producing organisms that were isolated from oil-contaminated soil samples were screened using Sudan Black stain. The maximum of 0.081gm/100 mL PHA was produced by isolates 3–6 which utilized sago liquid waste as carbonsource. The isolates 3–6 was identified to belong to Bacillus sp. and on scanning electron microscope, spherical PHA granules were observed which was compared to the reference strain. Further, PHA synthase was partially precipitated by ammonium sulfate followed by dialysis. Ion-exchange chromatography showed peak at 200 nm indicating the presence PHA synthase. Thus, the current study deals with optimization of media for PHA produced by Bacillus sp. at lab conditions can further be scaled up for large-scale production.