Production and characterization of polyhydroxyalkanoates by a novel strain Priestia flexa JP1

The study aimed at the production and characterization of biopolymer polyhydroxyalkanoate (PHA) by Bacillus endophyticus. The usage of refined (sucrose 2–4%) and inexpensive unrefined (sugar cane molasses 2–4%) carbon source was evaluated by varying the media components via shake flask method and batch cultivation in bioreactor. The optimal PHA production of 10.7 g/L of PHA from 15.37 g/L of cell density was obtained using 4% sugarcane molasses (SCM) at 250 rpm using optimized medium obtained through statistical experimental design. Batch cultivation with increased agitation rate and addition of feeding nutrients provided by SCM significantly lead to enhanced PHA production by the test organism by increasing the overall cell density. According to the statistical model, the increase in the sugar concentration (>4%) by SCM had a negative effect on PHA production. Characterization by FTIR and 1 H NMR was performed to confirm the biopolymer that has been produced by Bacillus spp.

Optimization and characterization of PHA from isolate Pannonibacter phragmitetus ERC8 using glycerol waste

Aims: This study aimed at screening, producing and characterizing polyhydroxyalkanoates (PHA) from lactic acid bacteria (LAB) isolated from dairy wastewater, fermented cow milk and “ogi”.
 Place and Duration of Study: Department of Microbiology, Faculty of Science, University of Ibadan, Ibadan between August 2018 and February 2019.
 Methodology: The initial screening of isolated LAB was carried out by Sudan Black staining method followed by secondary screening on liquid medium. Isolates that tested positive for Sudan Black stain and had the highest PHA yield from liquid medium was used for further analysis. The cell walls of selected isolates were lysed with sodium hypochlorite and PHA extracted using chloroform. Optimization of PHA production was carried out using different carbon and nitrogen sources, incubation temperature, pH and agitation speed. Extracted PHA was characterized by FTIR spectroscopy and the microstructure and surface morphology were observed using Scanning Electron Microscope.
 Results: Seven isolates tested positive for Sudan Black stain of which two isolates identified as Lactobacillus plantarum CW10 and Lactobacillus casei WWD3 had the highest PHA yield from liquid medium. From the optimization experiment, highest PHA production was observed in Lactobacillus plantarum CW10 (20.5%) and Lactobacillus casei WWD3 (19.7%) when glucose and ammonium sulphate was used as carbon and nitrogen sources respectively, and at pH 6, agitation speed of 200 rpm and incubation temperature of 35oC and 40oC. The spectra of extracted PHA as characterized by FTIR showed absorption peaks for the carbonyl, C-H, -OH, aliphatic -CH3 and ester groups that are characteristics of PHA. The microstructure and surface morphology shows grains that are pseudo-spherical in shape with fairly regular distribution.
 Conclusion: There is an appreciable production of PHA from the Lactobacillus strains and can be considered as part of the choice of organisms for PHA production in commercial quantity.

The production of biodegradable plastic from microorganisms has great potential as a substitute for conventional plastic. This study aims to isolate bacterial strains capable of polyhydroxyalkanoates (PHAs) production from the Kampung Jawa landfill land (KJLL) and characterize biopolymers. The bacterial strains were able to produce PHA using a mineral salt medium (MSM) with glucose as a carbon source. The qualitative screening of PHA-producing bacteria was conducted by Sudan Black and Nile Red. Of the 64 bacteria strains, only 41 were able to accumulate PHA in Sudan Black and Nile Red. The results showed that one bacteria the Coccobacillus strain had the highest color intensity for further characterization of PHA. The characterization of PHA by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) showed a melting temperature (Tm) of 101.54°C. X-ray diffraction (XRD) analysis revealed a crystalline structure with an index crystallinity (ICr) value of 15.82% for PHA. The results of the analysis proved that PHA was produced by bacteria isolate. This study suggests that this is the first report of the bacteria from the Kampung Jawa landfill producing PHA with good characteristics and potential biotechnology applications.

The accumulation of petrochemical plastics necessitates sustainable alternatives. This study investigated the production of polyhydroxyalkanoates (PHAs) using indigenous bacterial strains isolated from Balochistan's soils and five locally sourced food wastes: rice bran, potato peels, fruit pulp, dairy waste, and corn starch. The isolates were identified as Bacillus megaterium and Cupriavidusnecator via 16S rRNA sequencing. Fermentation parameters were systematically optimized for each strain. C. necator achieved a maximum PHA yield of 4.5 ± 0.3 g/L, constituting 85% of the cell dry weight, using Rice Bran at 30°C, pH 7.0, and 1% NaCl. Hydrothermal pretreatment increased yields by up to 36%, and nitrogen limitation enhanced polymer accumulation by 40-50%. Characterization by FTIR, NMR, and GC confirmed the synthesis of poly(3-hydroxybutyrate) (PHB) by B. megaterium and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with up to 33% hydroxyvalerate by C. necator. The PHBV copolymer exhibited a tensile strength of 32-40 MPa and a degradation temperature of 248-268°C, properties comparable to polypropylene. These results demonstrate that indigenous Balochistan strains efficiently convert regional food wastes into bioplastics with competitive material properties, establishing viable substrate-specific and strain-dependent bioprocessing strategy.

Optimization of the culture conditions for production of Polyhydroxyalkanoate and its characterization from a new Bacillus cereus sp. BNPI-92 strain, isolated from plastic waste dumping yard

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.

Biosynthesis and characterization of polyhydroxyalkanoate from marine Bacillus cereus MCCB 281 utilizing glycerol as carbon source

BackgroundSynthetic plastic pollution has increased tremendously over the past few decades. Supplanting synthetic plastics with a biodegradable alternative could save the biosphere from the drastic effects of plastic pollution. Polyhydroxyalkanoates (PHA) have been identified with the potential to become a feasible option.ResultsA bacterial strain isolated from pavement soil was investigated for its PHA production ability. The isolated strain was found to be non‐virulent, and susceptible to various antibiotics, especially cefalexin, tetracycline, chloramphenicol, norfloxacin and ofloxacin. The carbohydrate utilization profile revealed that isolated bacteria can utilize different carbohydrates with a variable rate of consumption. The 16S rRNA identification revealed that the strain was related to the Bacillus genus. The produced PHA was predicted to be polyhydroxybutyrate as suggested by differential scanning calorimetry and NMR, Fourier transform infrared and Raman spectroscopies. Moreover, the hydrophobic nature of the PHA produced was confirmed by contact angle measurement. The growth, production and substrate utilization kinetics revealed the specific growth rate of Bacillus sp. PhNs9 was 0.07 h−1, specific biomass productivity was 0.06 g L−1 h−1 and specific PHA productivity was 0.05 g L−1 h−1. The yield of PHA from biomass was found to be 0.67 g per gram of biomass.ConclusionsThe yield of PHA from the isolated strain was found to be higher than that of most earlier reports. Hence the findings of this study could catalyze the progress to completely move away from the use of synthetic plastics and replace them with an economical and sustainable solution. © 2022 Society of Chemical Industry (SCI).

BACKGROUNDPolyhydroxyalkanoates (PHAs) are natural biodegradable polymers synthesized by several microorganisms. Poly(3‐hydroxybutyrate) (PHB) is the most well‐characterized biopolymer produced abundantly by Bacillus species. In order to get a better PHA recovery, efficient pretreatment steps, especially dehydration, have a large impact on PHA purification from microbial PHA‐rich biomass. In this study, we have described the effects of lyophilization (‐L), microwave‐assisted drying (‐M) and ethanol/heat‐treatment (‐E) dehydration techniques on PHA production by B. megaterium NRRL B‐14308 strain.RESULTSAfter 66 h of batch cultivation, cells reached the maximum PHA accumulation (PHA‐L: 1.36 g L–1, PHA‐E: 1.55 g L–1, PHA‐M: 2.08 g L–1). The highest overall volumetric productivity for PHA was obtained as 0.226 g L–1 h‐1 for PHA‐M, which was 1.5‐fold higher than PHA‐L. Structural and thermal properties of PHA were characterized by GC–MS, FT‐IR, 1H‐NMR, TGA and DSC analyses. Analyses of the accumulated PHA by GC–MS, FT‐IR and 1H‐NMR revealed that the biopolymer was made up of 3‐hydroxybutyrate (3HB) and 3‐hydroxyvalerate(3 HV) monomers, irrespective of the dehydration technique.CONCLUSIONThe present study offers an alternative biomass drying technique (microwave‐assisted drying) to conventional drying techniques that is favorable in terms of energy efficiency and processing times, and should help to enhance biopolymer production processes. © 2018 Society of Chemical Industry

An investigation for recovery of polyhydroxyalkanoates (PHA) from Bacillus sp. BPPI-14 and Bacillus sp. BPPI-19 isolated from plastic waste landfill

The increasing awareness on the negative environmental impact of petroleum-based plastics has driven industries to explore more efficient biodegradable polymers for production of bioplastic. Polyhydroxyalkanoates (PHAs) is one of the potential biodegradable polymers to replace petroleum-based plastic. It is synthesized and accumulated as intracellular granules in microorganism. In this study, polyhydroxyalkanoates (PHAs) producing bacteria were successfully isolated from sediment collected from Kg. Batu Melintang hotspring. Isolation process was carried on Minimal Salt Medium (MSM) agar supplemented with excess glucose as a carbon source. Potential PHA producers were screened by using Nile Blue staining plate assay. Out of 144 bacterial isolates, 12 bacterial isolates which showed strong orange fluorescence under ultraviolet (UV) light (365nm) were selected for further identification by morphological characterization and biochemical analysis. Based on the result obtained, possible species for Gram positive rod shape bacteria B75 and B87 is Corynebacterium kutsceri meanwhile Gram negative rod shape bacteria A4, A12, A50, A68, B2, B13, B22, B31, B73 and C3 showed affiliation to Citrobacter sp., Enterobacter sp., Erwinia sp., Klebsiella sp., Proteus sp., Salmonella sp., Serratia sp., Shigella sp., and Yersinia sp.

Optimization, Production and Characterization of Polyhydroxyalkanoate (PHA) from Indigenously Isolated Novel Bacteria

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,Bacillussp., andLactococcus 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, theB. megateriumGRG 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.

In the context of circular economy and sustainable production of materials, this project investigated the feasibility of producing sustainable polyhydroxyalkanoates (PHA) from microalgae and sludge used in the treatment of municipal wastewater. The overall process was studied looking at the main steps: microalgae production, fermentation of the biomass, production and characterization of the PHAs. It was possible to obtain blends of hydroxybutyrate-hydroxyvalerate copolymers with high molecular weights and different compositions depending on the nature of the feedstock (mixed volatile fatty acids). In some cases, almost completely amorphous PHA materials were obtained, suggesting a potential diversification of uses and applications.