Bacterium Bacillus Sp Research Articles

Introduction of a Sodium-Binding Motif into Subunits <i>a</i> and <i>c</i> of <i>Bacillus</i> sp. PS3 Proton F-ATPase Does Not Result in Sodium Specificity of the Enzyme

In bacteria F-type ATPase (F-ATPase) plays a key role in bioenergetics and couples ATP synthesis/hydrolysis with the transport of ions (H+ or Na+) across the membrane. The ion specificity of the enzyme is determined by the amino acid sequence of subunits c and а. Here, we introduced several mutations (7 in subunit c and 6 in subunit a) into F-ATPase of thermophilic bacterium Bacillus sp. PS3 in order to change the ion specificity of the enzyme from proton to sodium. The mutations did not affect the ATPase activity of the enzyme, but led to loss of proton conductivity and impaired the binding of subunit a to the c-subunit oligomer, rather than changed the ion specificity.

Molecular Identification and Engineering a Salt-Tolerant GH11 Xylanase for Efficient Xylooligosaccharides Production.

This study identified a salt-tolerant GH11 xylanase, Xynst, which was isolated from a soil bacterium Bacillus sp. SC1 and can resist as high as 4 M NaCl. After rational design and high-throughput screening of site-directed mutant libraries, a double mutant W6F/Q7H with a 244% increase in catalytic activity and a 10 °C increment in optimal temperature was obtained. Both Xynst and W6F/Q7H xylanases were stimulated by high concentrations of salts. In particular, the activity of W6F/Q7H was more than eight times that of Xynst in the presence of 2 M NaCl at 65 °C. Kinetic parameters indicated they have the highest affinity for beechwood xylan (Km = 0.30 mg mL-1 for Xynst and 0.18 mg mL-1 for W6F/Q7H), and W6F/Q7H has very high catalytic efficiency (Kcat/Km = 15483.33 mL mg-1 s-1). Molecular dynamic simulation suggested that W6F/Q7H has a more compact overall structure, improved rigidity of the active pocket edge, and a flexible upper-end alpha helix. Hydrolysis of different xylans by W6F/Q7H released more xylooligosaccharides and yielded higher proportions of xylobiose and xylotriose than Xynst did. The conversion efficiencies of Xynst and W6F/Q7H on all tested xylans exceeded 20%, suggesting potential applications in the agricultural and food industries.

DESCRIPTION OF ORAL CAVITY MICROBIAL CULTURE IN DENTAL CARIES SUFFERERS

Background: Dental caries is one of the most common oral health problems worldwide, affecting 573 million children and 2.5 billion adults. Dental caries is a disease that attacks the hard tissues of the tooth, such as cementum, dentin, and enamel. This causes bacterial invasion, pulp death, and spread of infection to periapical tissues, which can cause pain. Purpose: The purpose of this study was to determine the microbial culture picture of the oral cavity of patients with dental caries. Methods: This research is descriptive and the samples in this study amounted to 7 samples of patients with dental caries at Dr. Sitanala Hospital, Tangerang City. The sampling technique in this study used purposive sampling technique. Results: The results of this study found 1 sample (14.3%) of Candida albicans fungus in fungal culture. In addition, 9 samples (64.3%) of Staphylococcus Sp. bacteria, 3 samples (21.4%) of Klebsiella Sp. bacteria, and 2 samples (14.3%) of Bacillus Sp. bacteria were found in the bacteria culture. Conclusion: It has been proven that the oral cavity of dental caries sufferers contains various kinds of microbes, such as the fungus Candida albicans, the bacteria Staphylococcus Sp., the bacteria Klebsiella Sp., and the bacteria Bacillus Sp..

The potential of indigenous Bacillus sp. BT3.1 as an antifungal biopesticide against the plant pathogen Fusarium oxysporum

Abstract. Nafidiastri FA, Lolita NT, Riqina HS, Aurora BZ, Geraldi A, Nurhariyati T, Supriyanto A, Ni’matuzahroh, Fatimah, Salamun. 2024. The potential of indigenous Bacillus sp. BT3.1 as an antifungal biopesticide against the plant pathogen Fusarium oxysporum. Biodiversitas 25: 2679-2686. Biosurfactants are green surfactants that bacteria can produce, one of which is Bacillus. This genus can produce lipopeptide-type biosurfactants, namely surfactin, that can inhibit the growth of fungal pathogens. This research aims to determine the biosurfactant activity on molasses substrates and the antifungal activity of isolate BT3.1 against Fusarium oxysporum. The biosurfactant activity test method tested hemolytic activity using the spot method, surface tension analysis, and emulsification activity. In addition, an antifungal activity test was also carried out using the swab method. Characterization of isolate BT3.1 was carried out macroscopically and microscopically. The macroscopic characteristics of isolate BT3.1 show that bacteria from the genus Bacillus are moderate in size, white, irregular with serrate colony edges, shiny raised elevations, and a shiny surface texture. Microscopic characteristics of the isolate showed Gram-positive bacteria with oval-shaped endospores in the center. Based on the results of the biosurfactant activity test, isolate BT3.1 showed beta-type hemolysis activity, reduced surface tension by 23.3 mN/m on distilled water and 12 mN/m on NB media, and produced an emulsion activity value of around 52%. The results of the production of crude extract of BT3.1 isolate on 2, 4, and 6% molasses substrates showed optimal biosurfactant activity at a concentration of 4% with an incubation time of 48 hours. The antifungal activity of isolate BT3.1 showed that 80% inhibited the growth of Fusarium oxysporum, so the indigenous bacteria Bacillus sp. BT-3.1 has the potential to be developed as a raw material candidate for antifungal biopesticides against the plant pathogen Fusarium oxysporum.

Biogenic Mn Oxide Generation and Mn(II) Removal by a Manganese Oxidizing Bacterium Bacillus sp. Strain M2.

Mn(II)-oxidizing bacteria (MOB) are widely distributed in natural environments and can convert soluble Mn(II) into insoluble Mn(III) and Mn(IV). The biogenic manganese oxides (BioMnOx) produced by MOB have been considered for remediating heavy metal pollution and degrading organic pollutants in an eco-friendly manner. In this study, a manganese-oxidizing bacterium was isolated from Mn-polluted rivulet sediment and identified as Bacillus sp. strain M2 by PCR, phylogenetic tree construction, transmission electron microscopy (TEM), and physiological and biochemical indices. Strain M2 grew well under Mn(II) stress. BioMnOx with nanosized irregular geometric shapes and loose structures generated by strain M2 were found on the surface of the bacterial cells. The content of Mn in the bacteria was as high as 5.36%. Approximately 71.24% and 47.52% of Mn(II) was oxidized to Mn(III/IV) in the cell and in the deposits, respectively, within 3 d of cultivation with Mn(II). Extracellular enzymes contributed to the Mn removal and oxidation. In conclusion, Bacillus sp. strain M2 has a high potential for use in the remediation of Mn-contaminated sites.

Purification and Characterization of a Novel Fibrinolytic Enzyme from Marine Bacterium Bacillus sp. S-3685 Isolated from the South China Sea.

A novel fibrinolytic enzyme, BSFE1, was isolated from the marine bacterium Bacillus sp. S-3685 (GenBank No.: KJ023685) found in the South China Sea. This enzyme, with a molecular weight of approximately 42 kDa and a specific activity of 736.4 U/mg, exhibited its highest activity at 37 °C in a phosphate buffer at pH 8.0. The fibrinolytic enzyme remained stable over a pH range of 7.5 to 10.0 and retained about 76% of its activity after being incubated at 37 °C for 2 h. The Km and Vmax values of the enzyme at 37 °C were determined to be 2.1 μM and 49.0 μmol min-1 mg-1, respectively. The fibrinolytic activity of BSFE1 was enhanced by Na+, Ba2+, K+, Co2+, Mn2+, Al3+, and Cu2+, while it was inhibited by Fe3+, Ca2+, Mg2+, Zn2+, and Fe2+. These findings indicate that the fibrinolytic enzyme isolated in this study exhibits a strong affinity for fibrin. Moreover, the enzyme we have purified demonstrates thrombolytic enzymatic activity. These characteristics make BSFE1 a promising candidate for thrombolytic therapy. In conclusion, the results obtained from this study suggest that our work holds potential in the development of agents for thrombolytic treatment.

Biodegradations of three different rank coals by a newly isolated bacterium Bacillus sp. XK1

Biodegradation of coal was closely related to coal rank. In this study, three kinds of coals whose coal ranks from high to low were Zhundong coal (ZDC), Hongshaquan coal (HSQC) and Heishan coal (HSC) were degraded by Bacillus sp. XK1 isolated from mine water. The degradation experiment results indicated that the degradation rate increased with the decrease of coal rank, and the highest degradation rate of HSC (low-rank coal) was 78.2 %, which was three times higher than that of ZDC (high-rank coal). The enzyme activity experiment showed that the alkaline protease and lignin peroxidase secreted by Bacillus sp. XK1 were key substances for coal biodegradation, and the alkaline protease activity and lignin peroxidase activity were all the highest in the presence of HSC, which were beneficial for coal biodegradation. The adsorption experiment found that HSC was more favorable to contact with Bacillus sp. XK1 than ZDC and HSQC. Furthermore, biodegradation products analysis suggested that with the decrease of coal rank, the contents of long chain alkanes in liquid products increased, among which the highest content of long chain alkane in liquid product of HSC was 86.98 %. The above experimental results demonstrated that biodegradation of low rank coal was an effective pathway.

Evaluation of Antibiotic Biodegradation by a Versatile and Highly Active Recombinant Laccase from the Thermoalkaliphilic Bacterium Bacillus sp. FNT.

Laccases are industrially relevant enzymes that have gained great biotechnological importance. To date, most are of fungal and mesophilic origin; however, enzymes from extremophiles possess an even greater potential to withstand industrial conditions. In this study, we evaluate the potential of a recombinant spore-coat laccase from the thermoalkaliphilic bacterium Bacillus sp. FNT (FNTL) to biodegrade antibiotics from the tetracycline, β-lactams, and fluoroquinolone families. This extremozyme was previously characterized as being thermostable and highly active in a wide range of temperatures (20-90 °C) and very versatile towards several structurally different substrates, including recalcitrant environmental pollutants such as PAHs and synthetic dyes. First, molecular docking analyses were employed for initial ligand affinity screening in the modeled active site of FNTL. Then, the in silico findings were experimentally tested with four highly consumed antibiotics, representatives of each family: tetracycline, oxytetracycline, amoxicillin, and ciprofloxacin. HPLC results indicate that FNTL with help of the natural redox mediator acetosyringone, can efficiently biodegrade 91, 90, and 82% of tetracycline (0.5 mg mL-1) in 24 h at 40, 30, and 20 °C, respectively, with no apparent ecotoxicity of the products on E. coli and B. subtilis. These results complement our previous studies, highlighting the potential of this extremozyme for application in wastewater bioremediation.

Structural characterization and high-efficiency prebiotic activity of the polysaccharide from Tremella aurantialba endophytic bacteria

Herein, the low-molecular-weight heteropolysaccharide (designated as TABP), with a weight-average Mw of 5408 Da, was produced by the endophytic bacterium Bacillus sp. TAB, which was initially isolated from the fruiting bodies of the wild Tremella aurantialba. A relatively high TABP accumulation was obtained and enhanced to 6.94 g/L in 5 L fed-batch fermentation by high-density cultivation. Monosaccharide composition analysis showed that the TABP comprised arabinose, glucosamine, galactose, glucose, and mannose with a molar ratio of 0.073: 0.145: 0.406: 0.182: 0.195, respectively. Methylation and NMR analyses indicated that TABP contained 1,4-linked β–d–Galp and 1,4-linked β–d–Manp pyranosyl backbone, extensively substituted at the side chains to form a complex structure. Prebiotic potential analysis exhibited significant growth-promoting effects for various lactic acid bacteria by more than 90 %. Overall, this study initially provides valuable insights into the endophytic exopolysaccharides from T. aurantialba and their biological activity, which provides prospective sources of prebiotics for functional foods and aids in understanding the endophytes symbiosis mechanism in edible mushrooms.

The role of an Sb-oxidizing bacterium in modulating antimony speciation and iron plaque formation to reduce the accumulation and toxicity of Sb in rice (Oryza sativa L.)

Microbial antimony (Sb) oxidation in the root rhizosphere and the formation of iron plaque (IP) on the root surface are considered as two separate strategies to mitigate Sb(III) phytotoxicity. Here, the effect of an Sb-oxidizing bacterium Bacillus sp. S3 on IP characteristics of rice exposed to Sb(III) and its alleviating effects on plant growth were investigated. The results revealed that Fe(II) supply promoted IP formation under Sb(III) stress. However, the formed IP facilitated rather than hindered the uptake of Sb by rice roots. In contrast, the combined application of Fe(II) and Bacillus sp. S3 effectively alleviated Sb(III) toxicity in rice, resulting in improved rice growth and photosynthesis, reduced oxidative stress levels, enhanced antioxidant systems, and restricted Sb uptake and translocation. Despite the ability of Bacillus sp. S3 to oxidize Fe(II), bacterial inoculation inhibited the formation of IP, resulting in a reduction in Sb absorption on IP and uptake into the roots. Additionally, the bacterial inoculum enhanced the transformation of Sb(III) to less toxic Sb(V) in the culture solution, further influencing the adsorption of Sb onto IP. These findings highlight the potential of combining microbial Sb oxidation and IP as an effective strategy for minimizing Sb toxicity in sustainable rice production systems.

Utilization POME as growth substrate for local indigenous bacteria Bacillus sp. ALP D1 in producing biosurfactant

Palm Oil Mill Effluent (POME) is a liquid palm oil waste that has beneficial value because of the nutritional content it contains. This research aim to obtain biosurfactant by using POME as a growth substrate. The methods used include biosurfactant production, extraction using acid precipitation, and characterization using TLC, FTIR, and LC-MS. The results showed that the local indigenous bacteria Bacillus sp. ALP D1 can produce biosurfactant under conditions of growth of POME 3%, NaNO3 3%, pH 6, salinity 7% with an IE24 of 69.44%, diameter of oil spreading test at 8.5 cm, and positive at drop collapse test. The extraction stage produces a brownish-yellow crude extract of 0.068 g/L. Biosurfactant characterization using TLC showed pink spots with ninhydrin reagent indicating the presence of nitrogen groups from peptide in the biosurfactant. This is supported by the results of FTIR analysis with the presence of an N-H peak from the peptide group in the absorption area 3384 cm-1. The results of the LC-MS analysis showed that the biosurfactant obtained had Rt 14.64 minutes and 332.22 m/z. Based on the results, it is suspected that the biosurfactant produced by Bacillus sp. ALP D1 is a lipopeptide.

Use of cerrado plants as an alternative in the control of bacterial contamination in the alcoholic fermentation process.

Bacterial contamination causes irreparable losses in the performance of alcoholic fermentation. Antibiotics are used to control these microorganisms, but they generate residues and cause microbial resistance. Today the only commercial product used by the mills is hops, but it is very expensive. As an alternative, the objective of this work was to evaluate the feasibility of using extracts from plants grown in the Cerrado for antimicrobial control during an alcoholic fermentation to replace antibiotics. Hydraethanolic extracts of leaves and essential oil of the following species were tested: Schinus terebinthifolius Raddi, Serjania erecta, Serjania marginata, Campomanesia adamantium and Syzygium cumini. Only the extract of Serjania marginata did not show any activity against the bacterium Bacillus sp. Both the essential oils as well as the hydroalcoholic extracts of S. terebinthifolius and C. adamantium and the extract of S. erecta showed antibacterial activity without harming the yeast, with potential to replace the hops.

Production of polyhydroxyalkanoates using sewage and cheese whey

Recently, polyhydroxyalkanoates (PHAs) have been produced using raw sewage in our laboratory; however, the production concentrations are low. Therefore, this study aimed to enhance PHA production by applying different strategies. PHA production was higher in sewage-containing medium than in mineral salt medium and was enhanced 22-fold after glucose supplementation. A relatively high degree of glucose consumption (83.6 ± 1.59 %) was also achieved. Bacteria incubated with cheese whey diluted with sewage showed higher PHA production than bacteria incubated with cheese whey diluted with distilled water did. The expression of the PHA synthase gene (phaC) was evaluated via real-time polymerase chain reaction using low- and high-carbon-containing sewage. Relatively higher phaC expression levels were observed in high-carbon-containing sewage but at lower nitrogen concentrations. The characteristics of the produced PHA were comparable to those of standard PHA. Therefore, this study revealed that the bacterium Bacillus sp. CYR1 can produce PHA from low- or high-carbon-containing wastewater.

The cryptic step in the biogeochemical tellurium (Te) cycle: Indirect elementary Te oxidation mediated by manganese-oxidizing bacteria Bacillus sp. FF-1

Tellurium (Te) is a rare element within the chalcogen group, and its biogeochemical cycle has been studied extensively. Tellurite (Te(IV)) is the most soluble Te species and is highly toxic to organisms. Chemical or biological Te(IV) reduction to elemental tellurium (Te0) is generally considered an effective detoxification route for Te(IV)-containing wastewater. This study unveils a previously unnoticed Te0 oxidation process mediated by the manganese-oxidizing bacterium Bacillus sp. FF-1. This bacterium, which exhibits both Mn(II)-oxidizing and Te(IV)-reducing abilities, can produce manganese oxides (BioMnOx) and Te0 (BioTe0) when exposed to Mn(II) and Te(IV), respectively. When 5 mM Mn(II) was added after incubating 0.1 mM or 1 mM Te(IV) with strain FF-1 for 16 h, BioTe0 was certainly re-oxidized to Te(IV) by BioMnOx. Chemogenic and exogenous biogenic Te0 can also be oxidized by BioMnOx, although at different rates. This study highlights a new transformation process of tellurium species mediated by manganese-oxidizing bacteria, revealing that the environmental fate and ecological risks of Te0 need to be re-evaluated.

Zinc solubilizing bacteria synergize the effect of zinc sulfate on growth, yield and grain zinc content of rice (Oryza sativa)

Zinc solubilizing bacteria inhabiting root endosphere possesses great potential to enhance plant yield by solubilizing the nutrients. The potential of Zn solubilizing bacteria Bacillus sp. SH-10 and Bacillus cereus SH-17 to improve yield and grain zinc content of rice was investigated under different regimes of individual and co-inoculation in the presence and absence of chemical fertilizer zinc sulfate (ZnSO4). The strains were applied to the rice varieties basmati 385 and super basmati under field conditions for two consecutive years. A significantly improved growth of rice plants, such as plant height (102–118 cm), number of tillers per plant (8.5–11.5), chlorophyll content (29.5–35.1), zinc requiring enzymes, i.e., superoxide dismutase (396–570 per gram fresh weight (g−1 FW)), carbonic anhydrase activity (CA) (10–15.06 U g−1 FW) and grain yield (3.0–3.8 tons ha−1), was observed in the plants inoculated with Bacillus sp. in the presence of chemical fertilizer (ZnSO4). Consortium of zinc solubilizing bacteria also caused higher grain Zn content (25.0–30.5 mg kg−1) of the rice varieties basmati 385 and super basmati as compared to that of un-inoculated plants. Hence, it can be concluded that Zn solubilizing bacteria has immense potential to be used as agricultural crop inoculants as they synergize the effect of chemical Zn, increase yield and improve the nutritional value of crops.

Plant growth-promoting bacteria modulate gene expression and induce antioxidant tolerance to alleviate synergistic toxicity from combined microplastic and Cd pollution in sorghum

Microplastics (MPs) can act as carriers for environmental pollutants; therefore, MPs combined with heavy metal pollution are attracting increasing attention from researchers. In this study, the potential of the plant growth-promoting bacterium Bacillus sp. SL-413 to mitigate the stress caused by exposure to both MPs and cadmium (Cd) in sorghum plants was investigated. The effects of inoculation on sorghum biomass were investigated using hydroponic experiments, and evaluation of Cd accumulation and enzyme activity changes and transcriptomics approaches were used to analyze its effect on sorghum gene expression. The results showed that combined polyethylene (PE) and Cd pollution reduced the length and the fresh and dry weights of sorghum plants and thus exerted a synergistic toxic effect. However, inoculation with the strains alleviated the stress caused by the combined pollution and significantly increased the biomass. Inoculation increased the dry weights of the aboveground and belowground parts by 11.5–44.6% and 14.9–38.4%, respectively. Plant physiological measurements indicated that inoculation reduced the reactive oxygen species (ROS) content of sorghum by 10.5–27.2% and thereby alleviated oxidative stress. Transcriptome sequencing showed that exposure to combined Cd+MP contamination induced downregulation of gene expression, particularly that of genes related to amino sugar and nucleotide sugar metabolism, starch and sucrose metabolism, and plant hormone signal transduction, in sorghum. However, inoculation with Bacillus sp. SL-413 resulted in an increase in the proportion of upregulated genes involved in signal transduction, antioxidant defense, cell wall biology, and other metabolic pathways, which included the phenylpropanoid biosynthesis, photosynthesis, flavonoid biosynthesis, and MAPK signaling pathways. The upregulation of these genes promoted the tolerance of sorghum under combined Cd+MP pollution stress and alleviated the stress induced by these conditions. This study provides the first demonstration that plant growth-promoting bacteria can alleviate the stress caused by combined pollution with MPs and Cd by regulating plant gene expression. These findings provide a reference for the combined plant-microbial remediation of MPs and Cd.

Pulsed electric field enhanced Bacillus sp. DL4 biodegradation of triclosan: focusing on operational performance and metabolomic analysis

ABSTRACT Electrochemical-assisted microbial degradation technology was considered a crucial strategy to reduce micropollutants, but the mechanism of the pulsed electric field (PEF) in affecting biodegradation had not been systematically studied. This study aimed to construct a bio-electrochemical system (BES) using PEF to investigate its effect on the degradation of triclosan (TCS) by the aerobic bacterium Bacillus sp. DL4. The operating optimal parameters for the BES (i.e. 0.01 A of the pulsed current, 1000 Hz of the pulse frequency, Fe (+)–C (−) of the plate materials, 4 cm of the plate spacing) were obtained by batch experiments. The maximum biomass (OD600 = 1.0 ± 0.05) was achieved and the removal efficiency of TCS reached above 95% in 24 h under the obtained operating conditions. Meanwhile, a thorough and methodical investigation of the metabolites in strain DL4 stimulated by PEF using untargeted Liquid Chromatography – Mass Spectrometry (LC-MS). In multivariate analysis, the experimental groups showed a notable separation in Principal Components Analysis (PCA) and Orthogonal Partial Least Squares Analysis discriminant analysis (OPLS-DA) score plots. A total of 3181 differential metabolites were obtained, and the up-regulated metabolites were mainly related to ‘Aminoacyl-tRNA biosynthesis’, ‘Arginine and proline metabolism’, ‘Lysine degradation’, ‘ABC transporters’, and ‘TCA cycle’, implying that PEF enhanced the degradation efficiency of TCS by enriching functional genes with transport ability and ion migration ability in cells. This study illuminated how PEF can affect TCS biodegradation and gives insights into the application prospect of electrochemical-assisted biodegradation technology in water environment treatment.

Identification, Isolation, Cloning, and Expression of a New Alkaline Serine Protease Gene from Native Iranian Bacillus sp. RAM 53 for Use in the Industry.

Proteases are one of the most important and widely applicable proteolytic enzymes that are used in various industries. The aim of this study was to identify, isolate, characterize, and clone the new extracellular alkaline protease from the native bacterium Bacillus sp. RAM53 that was isolated from rice fields in Iran. In this study, first, the primary assay of protease production was performed. The bacteria were cultured in a nutrient broth culture medium at 37° C for 48h, and then, the enzyme extraction was performed. Enzyme activity was measured by standard methods in the range of 20 to 60°C and the range of pH 6.0 to 12. Degenerate primers were designed to alkaline protease gene sequences. The isolated gene was cloned into the pET28a+ vector, the positive clones were transferred to Escherichia coli BL21, and the expression of the recombinant enzyme was optimized. The results showed that the optimum temperature and pH of the alkaline protease were 40° C and 9.0, respectively, and were stable at 60° C for 3h. The molecular weight of the recombinant enzyme was 40kDa in SDS-PAGE. The recombinant alkaline protease was inhibited by the PMSF inhibitor, indicating that the enzyme was serine protease. The results showed that the sequence alignment of the enzyme gene with the other alkaline protease gene sequences related to Bacillus was 94% identity. The result of Blastx showed about 86% identity to the S8 peptidase family in Bacillus cereus and Bacillus thuringiensis and other Bacillus species. The enzyme may be useful for various industries.

Quantification of the Monomer Compositions of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Poly(3-hydroxyvalerate) by Alkaline Hydrolysis and Using High-Performance Liquid Chromatography.

With the growing interest in bioplastics, there is an urgent need to develop rapid analysis methods linked to production technology development. This study focused on the production of a commercially non-available homopolymer, poly(3-hydroxyvalerate) (P(3HV)), and a commercially available copolymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)), through fermentation using two different bacterial strains. The bacteria Chromobacterium violaceum and Bacillus sp. CYR1 were used to produce P(3HV) and P(3HB-co-3HV), respectively. The bacterium Bacillus sp. CYR1 produced 415 mg/L of P(3HB-co-3HV) when incubated with acetic acid and valeric acid as the carbon sources, whereas the bacterium C. violaceum produced 0.198 g of P(3HV)/g dry biomass when incubated with sodium valerate as the carbon source. Additionally, we developed a fast, simple, and inexpensive method to quantify P(3HV) and P(3HB-co-3HV) using high-performance liquid chromatography (HPLC). As the alkaline decomposition of P(3HB-co-3HV) releases 2-butenoic acid (2BE) and 2-pentenoic acid (2PE), we were able to determine the concentration using HPLC. Moreover, calibration curves were prepared using standard 2BE and 2PE, along with sample 2BE and 2PE produced by the alkaline decomposition of poly(3-hydroxybutyrate) and P(3HV), respectively. Finally, the HPLC results obtained by our new method were compared using gas chromatography (GC) analysis.

Degradation profiling of in-vitro-produced polyhydroxyalkanoate synthesized by the soil bacterium Bacillus sp. PhNs9 under different microenvironments

Polyhydroxyalkanoates have been proven to be one of the best alternatives for synthetic plastics due to the similarity in their properties. The current study is focused on the natural degradation of the in vitro-produced PHA by the strain Bacillus sp. PhNs9. Different microenvironments were created to mimic different terrestrial and aqueous ecosystems. Maximum degradation of 98.62% was obtained in the soil while, in the case of aqueous systems, maximum degradation of 89.75% was found in the sewage wastewater in 30 days. The degradation profile of PHA was studied at different temperatures, pH, and moisture contents to ensure the degradation of produced PHA in different geographical locations having different environmental conditions. Different equations were obtained through a polynomial fitting for the prediction of degradation percentage at different conditions. The films were characterized using FTIR, Raman spectroscopy, drop shape analysis, and XRD which confirmed the decrease in both hydrophobicity and crystallinity of the films after degradation. This study established the natural degradation of the PHA produced by Bacillus sp. PhNs9 which could be commercialized without concerns about its accumulation in the environment.