Characterization Of Polyhydroxyalkanoates Research Articles

Isolation, screening, and characterization of polyhydroxyalkanoate (PHA)‐producing Cellulosimicrobium cellulans: A promising approach for eco‐friendly biopolymer production

AbstractThe replacement of synthetic plastics with eco‐friendly biopolymers is a notable approach in the modern world. Polyhydroxyalkanoates (PHAs) have gained a lot of attention among researchers in recent decades. This study aimed to isolate and screen microorganisms capable of producing PHA from composite samples. Several composting unit samples were collected and used to isolate 15 distinct colonies which were then screened for PHA synthesis. Three isolates‐SS2, SSNA 1a, and SF2‐showed promising PHA production. Among these isolates, SS2 had the highest PHA content of 70.1%. The isolate SS2 was determined as Cellulosimicrobium cellulans DSM 43879 by gene sequencing. The polymer produced by SS2 was further characterized. The presence of carbonyl groups and ester linkages in the PHA polymer was established by Fourier transform infrared analysis. The polymer's crystalline nature was validated by X‐ray powder diffraction measurement. Scanning electron microscope study revealed thread‐like forms with a rough surface while energy dispersive X‐ray analysis revealed a low impurity content that was primarily composed of carbon and oxygen with traces of other elements. Overall, the findings indicate C. cellulans potential as an ideal candidate for efficient PHA synthesis supporting its commercial potential in diverse applications.

Production, optimization, scale up and characterization of polyhydoxyalkanoates copolymers utilizing dairy processing waste

The microbial biotransformation using low-cost feedstock to produce biopolymers (degradable), an alternative to petrochemical-based synthesis plastics (non-degradable), can be a beneficial approach towards sustainable development. In this study, the dairy industry processes waste (whey) is used in polyhydroxyalkanoate (PHA) copolymer production. Initial screening suggested that Ralstonia eutropha produced higher PHA as compared to Bacillus megaterium. A central composite rotatable design-based optimization using two process variables (amino acid and tween-80) concentration remarkably influenced PHA co-polymer production under physiological conditions of pH (7), temperature (37 °C), and agitation rate of 150 rpm. High polyhydroxybutyrate (PHB) mass fraction yield of 69.3% was observed as compared to predicted yield of 62.8% from deproteinized whey as feed. The combination of tryptophan (50 mg L−1) and tween-80 (3 mL−1) enhanced R. eutropha mass gain to 6.80 g L−1 with PHB contents of 4.71 g L−1. Further, characterization of PHA and its copolymers was done by ESI–MS, FTIR, and TEM. On upscaling up to 3.0 L, the PHA contents and yields were noted as quite similar by R. eutropha. This study demonstrates that dairy waste processing waste can be potentially utilized as inexpensive feed for producing high content of biopolymers to develop a sustainable system of waste management.

Production and characterization of polyhydroxyalkanoates by Halomonas alkaliantarctica utilizing dairy waste as feedstock

Currently, the global demand for polyhydroxyalkanoates (PHAs) is significantly increasing. PHAs are produced by several bacteria that are an alternative source of synthetic polymers derived from petrochemical refineries. This study established a simple and more feasible process of PHA production by Halomonas alkaliantarctica using dairy waste as the only carbon source. The data confirmed that the analyzed halophile could metabolize cheese whey (CW) and cheese whey mother liquor (CWML) into biopolyesters. The highest yield of PHAs was 0.42 g/L in the cultivation supplemented with CWML. Furthermore, it was proved that PHA structure depended on the type of by-product from cheese manufacturing, its concentration, and the culture time. The results revealed that H. alkaliantarctica could produce P(3HB-co-3HV) copolymer in the cultivations with CW at 48 h and 72 h without adding of any precursors. Based on the data obtained from physicochemical and thermal analyses, the extracted copolymer was reported to have properties suitable for various applications. Overall, this study described a promising approach for valorizing of dairy waste as a future strategy of industrial waste management to produce high value microbial biopolymers.

Isolation and characterization of polyhydroxyalkanoate (PHA) producing bacteria isolate from landfill land of Kampung Jawa Banda Aceh

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.

Synthesis and characterization of polyhydroxyalkanoates from soil bacterium Bacillus sp. PhNs9

AbstractBackgroundSynthetic 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).

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

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

Production and Characterization of Polyhydroxyalkanoates from Wastewater via Mixed Microbial Cultures and Microalgae

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.

Production, downstream processing, and characterization of polyhydroxyalkanoates (PHAs) boosted by pyruvate supplement using mixed microbial culture (MMC) and organic wastewater

Production, downstream processing, and characterization of polyhydroxyalkanoates (PHAs) boosted by pyruvate supplement using mixed microbial culture (MMC) and organic wastewater

The Synthesis, Characterization and Applications of Polyhydroxyalkanoates (PHAs) and PHA-Based Nanoparticles.

Polyhydroxyalkanoates (PHAs) are storage granules found in bacteria that are essentially hydroxy fatty acid polyesters. PHA molecules appear in variety of structures, and amongst all types of PHAs, polyhydroxybutyrate (PHB) is used in versatile fields as it is a biodegradable, biocompatible, and ecologically safe thermoplastic. The unique physicochemical characteristics of these PHAs have made them applicable in nanotechnology, tissue engineering, and other biomedical applications. In this review, the optimization, extraction, and characterization of PHAs are described. Their production and application in nanotechnology are also portrayed in this review, and the precise and various production methods of PHA-based nanoparticles, such as emulsion solvent diffusion, nanoprecipitation, and dialysis are discussed. The characterization techniques such as UV-Vis, FTIR, SEM, Zeta Potential, and XRD are also elaborated.

Isolation and Characterization of Polyhydroxyalkanoates (PHAs) Producers from Kg Batu Melintang hotspring

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.

Production and characterization of polyhydroxyalkanoates from industrial waste using soil bacterial isolates.

Nowadays when conventional plastic is being looked as a menace, the possibility of it being replaced with polyhydroxyalkanoates (PHAs) which are biodegradable, environment friendly and biocompatible thermoplastics is not remote. PHAs are a fascinating group of biopolyesters stored within the cytoplasm of numerous bacterial cells as energy and carbon reserves. PHAs signify the best promising biological substitute to certain conventional petrochemical plastics which have wide range of applications in different industries such as biomedical sector, packaging, toners for printing, and adhesives for coating, etc. In the present study, PHAs producing bacterial strains were screened by Sudan black B staining and confirmed by Nile blue A staining. Out of forty bacterial strains showing positive results, six bacterial strains exhibited comparatively higher PHAs production. The highest PHAs producing bacterial strain was identified using 16s rRNA sequencing. Optimization of process parameters was performed by using one factor at a time (OFAT) approach. The isolated bacterium was able to synthesize PHAs when various agro-industrial wastes such as domestic kitchen waste, mixed fruit pulp, sugarcane molasses, and waste flour from bread factory were screened as a carbon substrate in the growth medium. The results showed accumulation of 44.5% PHAs of cell dry weight using domestic kitchen waste as carbon substrate. The characterization of biopolymers was performed using FTIR and XRD analysis. The commercial exploitation of results of this study may serve twin purposes of addressing the challenge of high production cost of PHAs being the major constraint in replacing petro-based plastics as well as address the problem of disposal of recurring domestic kitchen waste and other agro-industrial waste.

Production and Characterization of Polyhydroxyalkanoates from Lactic Acid Bacteria Isolated from Dairy Wastewater, Fermented Cow Milk and ‘Ogi’

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.

Downstream processing and characterization of polyhydroxyalkanoates (PHAs) produced by mixed microbial culture (MMC) and organic urban waste as substrate

The utilization of food waste and sewage sludge as organic substrate from urban context for the synthesis of microbial polyhydroxyalkanoates (PHAs) has been only recently investigated at pilot scale. Within this context, two stabilization methods have been found for preserving the amount of PHA intracellularly produced by open mixed microbial culture (MMC): thermal drying and wet acidification of the biomass at the end of PHA accumulation process. The extracted PHA from the two differently stabilized biomasses was then characterized with regard to chemical composition, molecular weight, and thermal properties. The polymer contained two types of monomers, namely 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) at a relative percentage of 93.0–79.8 and 7.0–20.2 w/w, respectively. PHA extracted from wet-acidified biomass had higher average molecular weights (Mw) of 370–424 kDa while PHA recovered from thermally stabilized dried biomass had a 3-fold lower Mw (on average). The PHA decomposition temperatures Td10% and Tdmax were in the range 260–268 °C and 269–303 °C, respectively, not dependent on the monomeric composition or molecular weight. Thermal properties such as melting temperature (Tm1 132–150 °C; Tm2 155–167 °C) and melting enthalpy (26–70 J/g) were quantified in a relatively broad range according to the different stabilization-extraction method and obtained composition.

Production and characterization of polyhydroxyalkanoates (PHAS) produced from bacillus cereus MUL-A isolated from biogas digester

Production and characterization of polyhydroxyalkanoates (PHAS) produced from bacillus cereus MUL-A isolated from biogas digester

Production of Polyhydroxyalkanoates (PHA) for Biomedical Application using Sugar Industry Waste and Native Micro Flora via Biphasic System.

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.

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

The aim of this study was to optimize the culture conditions for production, recovery and characterization of polyhydroxyalkanoate (PHA) from potential Bacillus cereus strain BNPI-92. Cost effective carbon sources such as crude oil (CO), rice bran (RB), sugar cane molasses (SCM) and wheat bran (WB) were evaluated for PHA production using the isolate. Higher cell dry weight (CDW) (g/L), PHA concentration (P conc.) (g/L) PHA contents (PC) (%) and PHA synthesis rate (PSR) were obtained from Glucose (60.67% w/v) as a carbon source at 37 °C and pH 7 using Taguchi DOE methods. The polymer was characterized by FTIR and its functional groups (C=O) (1719.41 cm−1 wavenumber) was a characteristic feature of PHB polymer. For 1HNMR, signals of methyne (CH) (5.28 ppm), methylene (-CH2-) (2.45 ppm) and methyl (CH3) (1.27 ppm) and copolymers were predicted. Copolymers such as P (3HB-co-3 HV) and P(3HB-co-3HHX) i.e. characteristic feature of PHB were obtained from a sample of glucose, WB, and RB, respectively. XRD pattern also confirmed the presence of PHA. The major compounds obtained from GC/MS analysis of the polymer recovered from the isolate BNP-92 were 2-butenoic acid, methyl ester (8.6%), ethyl cyclopropanecarboxylate (45.99%), 1-Undecanol (10.18%) which corresponds to and have produced from PHA after thermal degradation.

Extraction and characterization of polyhydroxyalkanoates from marine green alga and cyanobacteria

Abstract The present study focusses on the extraction and characterization of polyhydroxyalkanoates from marine algal species by solvent extraction method. The following strains (i) Chlorella sp., (ii) Oscillatoria salina, (iii) Leptolyngbya valderiana and (iv) Synechococcus elongatus were used in the present research work. Algal strains were scaled up in ASN III medium and preliminary bioprospecting study was conducted to evaluate the growth profile of all algal strains in terms of dry cell weight. Of the strains studied, the higher growth was observed with Leptolyngbya valderiana and Chlorella sp. at about 2.75 g/L whereas Oscillatoria salina and Synechococcus elongatus showed low dry cell weight of 0.99 g/L and 0.32 g/L respectively. In addition, extraction of polyhydroxyalkanoates from the algal strains were carried out and characterized. Thermo Gravimetric Analysis and Differential Scanning Calorimetry studies were conducted to determine the thermal stability and thermal properties of the synthesized PHA respectively. All the PHAs were thermally stable below 260 °C. PHA obtained from Leptolyngbya valderiana was found to be more thermally stable compared to the PHA obtained from other algal species.

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

Bio-plastic synthesis from renewable and cheap agro-based materials is a sustainable solution for replacing conventionally produced plastic with environmental contamination. The current study was aimed at screening and characterization of Polyhydroxyalkanoates (PHA) producing bacterial isolates, evaluation of their potential and recovery of PHA using the isolates. The PHA compounds were characterized using FT-IR. Based on 16SrRNA sequence analyses the isolates were designated as Bacillus sp. BPPI-14 and Bacillus sp. BPPI-19. The isolates were gram-positive, rod-shaped, endospore former, and citrate test positive. Intracellular PHA granules were observed when these isolates were stained with Sudan black B (SBB) and Nile blue A (NBA) preliminary and specific staining dyes, respectively. Effect of pH, temperature and carbon sources on the PHA production by the isolates BPPI-14 and BPPI-19 was studied. Maximum PHA production was recorded for Glucose (49.46±2.79%) by Bacillus sp. BPPI-14 and followed by molasses (45.86±2.17%) by Bacillus sp. BPPI-19, respectively at 37°C and pH7. The obtained PHA polymers were confirmed by preparation of plastic films for both the isolates. Fourier transform infrared spectrum for BPPI-14 and BPPI-19 showed the peak (carboxylic acid group) at 1706–1719.39cm−1 was a characteristic feature of PHA and corresponds functional group (C=O).

Synthesis and Characterization of Polyhydroxyalkanoate Organo/Hydrogels.

Synthetic organogels/hydrogels are attracting growing interests due to their potential applications in biomedical fields, organic electronics, and photovoltaics. Photogelation methods for synthesis of organogels/hydrogels have been shown particularly promising because of the high efficiency and simple synthetic procedures. This study synthesized new biodegradable polyhydroxyalkanoates (PHA)-based organogels/hydrogels via UV photo-cross-linking using unsaturated PHA copolymer poly[(R)-3-hydroxyundecanoate-co-(R)-3-hydroxy-10-undecenoate] (PHU10U) with polyethylene glycol dithiol (PDT) as a photo-cross-linker. The PHU10U was synthesized by an engineered Pseudomonas entomophila and characterized via Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance (NMR), and 13C NMR. With decreasing the molar ratio of PHU10U to PDT, both the swelling ratio and pore size were decreased. Meanwhile, increasing densities of the gel networks resulted in a higher compressive modulus. Cell cytotoxicity studies based on the CCK-8 assay on both the PHU10U precursor and PHU10U/PDT hydrogels showed that the novel PHA-based biodegradables acting as hydrogels possess good biocompatibility.

Improvement of the Production and Characterisation of Polyhydroxyalkanoate by Bacillus endophyticus Using Inexpensive Carbon Feedstock

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.