A laboratory case study of efficient polyhydoxyalkonates production by Bacillus cereus, a contaminant in Saccharophagus degradans ATCC 43961 in minimal sea salt media

Black rice bioactive with multifunctional health promotional activities: A special reference to wound healing activity with polyhydroxybutyrate composite

Black rice (BR) extract contains several functional food bioactive components that are health-promoting. This study assessed the multifunctional bioactivities of various BR extracts (methanol, ethanol, acetone, and aqueous). These BR extracts revealed significant antioxidant and antibacterial activity against various bacterial strains. Acetone extract exhibited high cytotoxicity against gastric adenocarcinoma cells (AGS), while ethanol extract was cytotoxic against pancreatic cancer cells (PANC-1). Moreover, the acetone extract induced 33.6 % and 16.5 % apoptosis in PANC-1 and AGS cells, respectively. Acetone extract showed significant anti-inflammatory action, reducing 76 % production of nitric oxide in the RAW 264.7 (murine macrophage). Furthermore, all BR extracts inhibited PANC-1 and AGS migration and promoted RAW 264.7 migration. Field emission scanning electron microscope, Fourier-transform infrared spectroscopy, and X-ray diffraction analysis of the BR-polyhydroxybutyrate composite revealed successful deposition for BR extracts. This study highlights the potential of BR extracts to develop multifunctional activity-based strips for rapid wound healing.

Production of polyhydroxyalkanoate from new isolated bacteria of Acidovorax diaphorobacter ZCH-15 using orange peel and its underlying metabolic mechanisms

Polyhydroxyalkanoate (PHA) is considered a sustainable alternative to traditional petroleum-based plastics due to its biodegradability and biocompatibility. In this study, Acidovorax diaphorobacter ZCH-15, an efficient PHA-producing strain, was isolated from activated sludge. Using food waste-derived orange peel as a substrate, the strain initially achieved a PHA concentration of 0.39 g/L. Under optimal fermentation conditions (30℃, pH 8, 2 % inoculum concentration, and 30 g/L carbon source), the PHA concentration increased by 138 % to reach a maximum of 0.93 g/L. Proton nuclear magnetic resonance spectroscopy and gas chromatography analyses identified the PHA composition as poly(3-hydroxybutyrate-co-3-hydroxyvalerate), which exhibited high crystallinity and structural stability. Metabolomic analysis indicated that the tricarboxylic acid cycle and pentose phosphate pathway were involved in producing succinyl-CoA, a precursor required for PHA synthesis. This study demonstrates the potential for cost-effective industrial PHA production while enabling the high-value utilization of food waste.

Cupriavidus necator-Produced Polyhydroxybutyrate/Eudragit FS Hybrid Nanoparticles Mitigates Ulcerative Colitis via Colon-Targeted Delivery of Cyclosporine A

Polyhydroxybutyrate (PHB) has emerged as a novel material for replacing various plastics used in the medical field. However, its application as a drug-delivery carrier for colitis-targeted delivery has not been explored. In this study, we used biosynthesized PHB combined with Eudragit FS (EFS) and cyclosporine A (CSA) to develop pH-responsive controlled CSA-releasing nanoparticles (CSA-PENPs) for colitis-targeted drug delivery and demonstrated its enhanced therapeutic efficacy in a dextran sulfate sodium (DSS)-induced murine colitis model. PHB was successfully biosynthesized in the bacterium Cupriavidus necator, as demonstrated by ¹H-NMR and FT-IR analyses. CSA-PENPs were fabricated via the oil-in-water emulsion solvent evaporation method. Owing to the potent pH-responsive and sustained drug release properties provided by PHB and EFS, CSA-PENPs could deliver a sufficient amount of CSA to inflamed tissues in the distal colon; in contrast, CSA-loaded EFS nanoparticles displayed premature burst release before reaching the target site. Due to enhanced CSA delivery to colitis tissues, CSA-PENPs exhibited potent anti-inflammatory effects in the DSS-induced murine colitis model. Overall, CSA-PENPs could be a promising drug-delivery system for treating ulcerative colitis.

Polyhydroxyalkanoate recovery from newly screened Bacillus sp. LPPI-18 using various methods of extraction from Loktak Lake sediment sample

BACKGROUND

Nowadays, the conventional plastic wastes are very challenging to environments and its production cost also creates an economic crisis due to petrochemical-based plastic. In order to solve this problem, the current studies were aimed at screening and characterizing these polyhydroxyalkanoate (PHA)-producing isolates and evaluating the suitability of some carbon source for newly screened PHA-producing isolates.

MATERIAL AND METHODS

Some carbon sources such as D-fructose, glucose, molasses, D-ribose and sucrose were evaluated for PHA production. Data were analyzed using SPSS version 20. The 16SrRNA gene sequence of these isolates was performed. These newly isolated taxa were related to Bacillus species. It was designated as Bacillus sp. LPPI-18 and affiliated Bacillus cereus ATCC 14577^T (AE01687) (99.10%). Paenibacillus sp. 172 (AF273740.1) was used as an outgroup.

RESULTS

Bacillus sp. LPPI-18 is a gram-positive, rod-shaped, endospore former, and citrate test positive. This isolate showed positive for amylase, catalase, pectinase, and protease test. They produced intracellular PHA granules when this isolate was stained with Sudan Black B (SBB) and Nile blue A (NBA) preliminary and specific staining dyes, respectively. Both temperature and pH used to affect polyhydroxyalkanoates (PHA) productivity. Bacteria are able to reserve PHA in the form of granules during stress conditions. This isolate produces only when supplied with carbon sources. More PHA contents (PCs) were obtained from glucose, molasses, and D-fructose. In this regard, the maximum mean value of PC was obtained from glucose (40.55±0.7%) and the minimum was obtained from D-ribose (12.4±1.4%). Great variations (P≤0.05) of PCs were observed among glucose and sucrose, molasses and sucrose, and D-fructose and sucrose carbon sources for PHA productivity (PP) of cell dry weight (CDW) g/L. After extraction, PHA film was produced for this typical isolate using glucose as a sole carbon source. Fourier transform infrared spectrum was performed for this isolate and showed the feature of polyester at 1719.64 to 1721.16 wavelengths for these extracted samples. The peak of fingerprinting (band of carboxylic acid group) at this wavelength is a characteristic feature of polyhydroxybutyrate (PHB) and corresponds to the ester functional group (C=O).

CONCLUSION

In this study, newly identified Bacillus sp. LPPI-18 is found to be producing biodegradable polymers that are used to replace highly pollutant conventional plastic polymers. This isolate is also used to employ certain cost-effective carbon sources for the production of PHA polymers.

Production of polyhydroxyalkanoates by halotolerant bacteria with volatile fatty acids from food waste as carbon source

In this study, a halotolerant strain was isolated from high salinity leachate and identified as Bacillus cereus NT-3. It can produce a high concentration of polyhydroxyalkanoates (PHAs) with no significant changes when NaCl concentration is up to 50 g/L. FTIR and NMR spectra of PHAs synthesized by Bacillus cereus NT-3 were similar to the standard or previous results. Effluent from acidogenic fermentation of food waste and pure volatile fatty acids (VFAs) mixture was used as carbon source to check the effect of non-VFAs compounds of the effluent on PHAs production. The maximum PHAs production was 0.42 g/L for effluent fermentation, whereas it was 0.34 g/L for pure VFAs fermentation, indicating that bacteria could use actual effluent in a better way. Furthermore, a mathematical model was established for describing kinetic behavior of bacteria using different carbon sources. These results provided a promising approach for PHAs biosynthesis with a low-cost carbon source.

Recent Advances and Challenges towards Sustainable Polyhydroxyalkanoate (PHA) Production

Sustainable biofuels, biomaterials, and fine chemicals production is a critical matter that research teams around the globe are focusing on nowadays. Polyhydroxyalkanoates represent one of the biomaterials of the future due to their physicochemical properties, biodegradability, and biocompatibility. Designing efficient and economic bioprocesses, combined with the respective social and environmental benefits, has brought together scientists from different backgrounds highlighting the multidisciplinary character of such a venture. In the current review, challenges and opportunities regarding polyhydroxyalkanoate production are presented and discussed, covering key steps of their overall production process by applying pure and mixed culture biotechnology, from raw bioprocess development to downstream processing.

Discovery of a mcl-PHA with unexpected biotechnical properties: the marine environment of French Polynesia as a source for PHA-producing bacteria

A library of microorganisms originating from various marine environments in French Polynesia was screened for polyhydroxyalkanoate producing bacteria. No significant connection was found between the geo-ecological source of bacteria and their ability to produce polyhydroxyalkanoate. A bacterial strain designated as Enterobacter FAK 1384 was isolated from a shark jaw. When grown on coprah oil, this bacterium produces a PHA constituting of 62 mol % 3-hydroxydecanoate and lower amount of 12 mol % 3-hydroxydodecenoate and of 7.6 mol % 3-hydroxydodecanoate. These interesting properties make this mcl-PHA a good candidate for further exploitations in many industrial sectors, as in film and coating manufacturing, as well as for biomedical applications.

Comparative study of MnO2 nanoparticle synthesis by marine bacterium Saccharophagus degradans and yeast Saccharomyces cerevisiae

Microorganisms are one of the most attractive and simple sources for the synthesis of different types of metal nanoparticles. The synthesis of manganese dioxide nanoparticles (MnO2 NPs) by microorganisms from reducing potassium permanganate was investigated for the first time in the present study. The microbial supernatants of the bacterium Saccharophagus degradans ATCC 43961 (Sde 2-40) and of the yeast Saccharomyces cerevisiae showed positive reactions to the synthesis of MnO2 NPs by displaying a change of color in the permanganate solution from purple to yellow. KMnO4-specific peaks also disappeared and MnO2-specific peaks emerged at an absorption maximum of 365 nm in UV-visible spectrophotometry. The washed Sde 2-40 cells did not show any ability to synthesize MnO2 NPs. The medium and medium constituents of Sde 2-40 showed similar positive reactions as supernatants, which indicate the role of the Sde 2-40 medium constituents in the synthesis of MnO2 NPs. This suggests that microorganisms without nanoparticle synthesis ability can be misreported for their abilities to synthesize nanoparticles. S. cerevisiae washed cells showed an ability to synthesize MnO2 NPs. The strategies of keeping yeast cells in tea bags and dialysis membranes showed positive tests for the synthesis of MnO2 NPs. A Fourier transform-infrared spectroscopy study suggested roles for the proteins, alcoholic compounds, and cell walls of S. cerevisiae cells in the synthesis of MnO2 NPs. Electron-dispersive X-ray spectroscopy analyses confirmed the presence of Mn and O in the sample. X-ray photoelectron spectroscopy revealed characteristic binding energies for MnO2 NPs. Transmission electron microscopy micrographs revealed the presence of uniformly dispersed hexagonal- and spherical-shaped particles with an average size of 34.4 nm. The synthesis approach using yeast is possible by a simple reaction at low temperature without any need for catalysts, templates, or expensive and precise equipment. Therefore, this study will be useful for the easy, cost-effective, reliable, and eco-friendly production of nanomaterials.