Media engineering for production of poly-β-hydroxybutyrate by Bacillus firmus NII 0830 (original) (raw)
Related papers
2016
Polyhydroxybutyrate (PHB) is polyester produced by a range of microbes under unfavorable growth conditions and stored as an intracellular carbon and energy material. PHB production is more expensive than petrochemical polymer production. The main production cost is the cost of carbon substrate. The aim of this study is to produce PHB using a cheap carbon source, crude glycerol, which is a major byproduct in the biodiesel manufacturing process. PHB producing bacteria species were isolated from the soil collected around biodiesel plants and screened by Nile Red staining method. The effects of sources and concentrations of crude glycerol on the biosynthesis of PHB were investigated. The maximum PHB content obtained after 24 hours of batch cultivation was 23.59 % of cell dry weight at initial crude glycerol of 10 g/L and C:N ratio of 1:0.4.
This study presents Bacillus firmus NII 0830 for producing poly-3-hydroxybutyrate (PHB) using biodiesel industry generated glycerol, a waste by-product, as sole carbon source under submerged fermentation and production process was optimized using statistical experimental design. PHB accumulation was observed up to 1.60 g/l from 4.36 g/l of total bacterial biomass at inoculum size of 3% v/v, incubation temperature 30°C, crude glycerol concentration 5% v/v, 250 RPM, incubation time 60 h and media pH 6.0 during initial statistical design. Further Response Surface design experiments yielded 61% of PHB from B. firmus NII 0830. Glycerol has a low market price and it does not require any further refinement, makes present process more economical. Further, utilization of low-grade waste glycerol solves its disposal problem, hence it is aptly an environmentally friendly 'waste to wealth' bioprocess.
Annals of Microbiology, 2013
A newly isolated poly(3-hydroxybutyrate) [P(3HB)] producing strain, ST1C, was identified as Bacillus aryabhattai based on its morphological, biochemical and molecular characteristics. It synthesized and accumulated relatively high amounts of P(3HB). The aim of this work was to establish if it could convert an inexpensive liquid waste product from the production of biodiesel, biodiesel liquid waste (BLW), to P(3HB). Using a mineral salt medium (MSM) containing 2.0 % (v/v) glycerol present in the BLW and both normal batch and a draw and fill culture method, B. aryabhattai ST1C produced a maximum P(3HB) content and biomass concentration of 72.31 % dry cell weight (DCW) and 7.24 g/L, respectively, over a 24 h cultivation period in the draw and fill cultivation method. From 24 h to the end of cultivation at 72 h both the P(3HB) content and the biomass concentrations continuously reduced. Concentrations of glycerol in the BLW in this MSM above 3.0 % (v/v) or from pure glycerol (PG) or with an added NaCl concentration of greater than 3.0 % significantly reduced both the maximum P(3HB) content and the biomass concentrations.
DYNA
The operating conditions of polyhydroxybutyrate (PHB) production processes are among the factors that most influence yields. In this study, we evaluated PHB production synthesized by Bacillus megaterium LVN01. Batch and fed-batch cultures were used to produce PHB from residual glycerol. For this, dry cell weight (DCW) and PHB productivity were analyzed at a preliminary stage by central composite design using batch systems under different temperature, C/N ratio, and fermentation time conditions. The maximum PHB productivity occurred at 30.8 °C, 44.9 mol mol-1, and 39.9 h. The same conditions were tested for studies in fed-batch culture. Fed-batch experiments were comparable to each other, where the DCW was around 1.9 g L-1, with PHB productivities of 29.5 mg L-1 h-1 and 35.6 mg L-1 h-1 for bioreactors of 5 L and 14 L, respectively. The PHB was characterized by NMR, FTIR, DSC, TGA, and DTG analys
Brazilian Archives of Biology and Technology, 2009
The aim of this work was to study the production of polyhydroxybutyrate (PHB) using agro-industrial residues as the carbon source. Seven substrates, viz., wheat bran, potato starch, sesame oil cake, groundnut oil cake, cassava powder, jackfruit seed powder and corn flour were hydrolyzed using commercial enzymes and the hydrolyzates assessed for selecting the best substrate for PHB production. Jackfruit seed powder gave the maximum production of PHB under submerged fermentation using Bacillus sphaericus (19%) at the initial pH of 7.5.
Journal of Applied Polymer Science, 2012
This study focused on the characterization of polyhydroxybutyrate (PHB) produced from crude glycerol (CG) using mixed microbial consortia (MMC). PHB recovered from two biomass drying treatments (65 C oven drying and lyophilization) was characterized comparatively along with a commercially sourced PHB (PHB-C). Characterization results showed that ovendrying method caused PHB partial hydrolysis, as indicated by its lower molecular weight (M w) (PHB-O, 144,000 g mol À1), which further affected its physical and chemical properties. Lyophilization helped alleviate PHB hydrolysis during drying process, leading to PHB (PHB-L) of higher M w (309,000 g mol À1) and material properties comparable with commercial PHB. Furthermore, crystallization and morphological studies showed that PHB-L featured faster crystallization rates and smaller spherulites as compared with PHB-C, probably due to its lower M w. In general, the results from this study suggested that CG-MMC-derived PHB-L possessed material properties comparable with those of pure substrate/culture produced PHB. V
Agricultural Engineering International: The CIGR Journal, 2008
The accumulation of polyhydroxybutyrate (PHB) granule in cells of Bacillus megaterium ATCC 6748 was significantly depended on the ratio of C-source and N-source in the medium culture. Sugarcane molasses (MOL) and corn steep liquor (CSL) were used as renewable raw materials, since they were rich in carbon and nitrogen respectively, leading to develop a low cost process of PHB production. The highest PHB production was observed after 45h of growth (43% w/w, dry matter) when 4% molasses and 4% CSL were used, whereas the highest biomass (7.2 g l-1) was obtained at 4% molasses and 6% CSL. This indicated that bacterial growth increased as CSL concentration increased, whereas the PHB accumulation decreased. The formation rate of PHB up to 0.016 h-1 and specific growth rate up to 0.25 h-1 were observed during growth. The chemical structure and thermal properties of PHB produced from molasses and CSL were obtained the same properties as commercial PHB, except for the higher molecular mass (approx. 3.9 x 10 6 Da) and the lower degree of crystallinity (60% X C). Thus, the present data indicate that molasses and CSL could be alternatively used for PHB production by this bacterium with high PHB content and adequate properties of biopolymer from a low cost process.
Potential of Bacillus sp. to produce polyhydroxybutyrate from biowaste
Journal of Applied Microbiology, 2009
Aim: To test the Bacillus strains for their abilities to produce polyhydroxybutyrate (PHB) from different sugars and biowaste (Pea-shells).Methods and Results: Six Bacillus strains were checked for their ability to produce PHB from GM2 medium supplemented with different sugars at the rate of 1% (w/v) and from biowaste and GM2 (BW : M) combinations (3 : 7, 1 : 1, 7 : 3). Glucose supplemented GM2 medium resulted in maximum PHB production of 435 mg l−1 constituting 31–62% w/w of the total cell dry mass. Substituting GM2 medium to the extent of 50% with biowaste (pea-shell slurry) resulted in 945–1205 mg l−1 PHB (55–65% w/w). Optimization for additional nitrogen supplementation, inoculum size resulted in a final PHB production of 3010–3370 mg l−1 equivalent to 300 g kg−1 biowaste (dry wt).Conclusion: The Bacillus strains were able to produce PHB from biowaste (Pea-shells) as cheap source of substrate.Significance and Impact of the Study: This is the first report on usage of pea-shells as feed for PHB production, opening new possibilities for its use for production of PHB and Bacillus as potential candidate for the purpose.
Journal of Renewable Materials, 2017
Biodegradable polymers from renewable resources are generating growing interest in the plastic industry because they have properties similar to synthetic polymers. Polyhydroxyalkanoates, mainly polyhydroxybutyrate (PHB), have mechanical and physicochemical properties very similar to their synthetic counterparts. This work explores the use of residual glycerol from the bioenergy industry for the production of PHB by Bacillus megaterium DSM 32. The glycerol works as a source of carbon and energy. Raw glycerol was purified with sulfuric acid in order to neutralize saponified fatty acids. The purification process generated three different phases. One of the phases was the glycerol-rich layer; this layer was filtered and concentrated by vacuum distillation process. The purity of the glycerol was determined by thermogravimetric analysis (TGA). Additionally, the physicochemical properties, like viscosity, pH, ash content and density, were measured. The experiments were conducted in shake flasks at 30 °C and 120 rpm. Different glycerol concentrations (20, 30, 40 g/L) were used to evaluate the influence of the initial concentration of glycerol on the biomass accumulation and biopolymer production. The purified glycerol obtained had a high purity (~ 89.5-92.13%); this material does not contain fatty acids, although it contains ~3.7% salts. The final PHB concentration obtained was 0.054 mg/mL.