A sustainable synthesis of polyhydroxyalkanoate from stubble waste as a carbon source using Pseudomonas putida MTCC 2475.

Polyhydroxyalkanoates (PHAs) are biodegradable polymers that can be produced from lignocellulosic biomass by microorganisms. Cheap and readily available raw material, such as corn stover waste, has the potential to lessen the cost of PHA synthesis. In this research study, corn stover is pretreated with NaOH under conditions optimized for high cellulose and low lignin with central composite design (CCD) followed by characterization using Fourier-transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). Design expert software performed further optimization of alkali pretreated corn stover for high total reducing sugar (TRS) enhancement using CCD using response surface methodology (RSM). The optimized condition by RSM produced a TRS yield of 707.19 mg/g. Fermentation using corn stover hydrolysate by Pseudomonas putida MTCC 2475 gave mcl-PHA detected through gas c hromatography - t andem m ass s pectrometry (GC-MS/MS) and characterization of the PHA film by differential scanning calorimetry (DSC), FTIR, and nuclear magnetic resonance (NMR). Thus, this research paper focuses on using agriculture (stubble) waste as an alternative feedstock for PHA production.

Acid hydrolysis of Solanum tuberosum periderm for accumulation of polyhydroxyalkanoates in Pseudomonas putida MTCC 2475.

Polyhydroxyalkanoates are a class of biodegradable, biocompatible polymers composed of polyesters of R-hydroxyalkanoic acids and deposited intracellularly by a variety of microorganisms which have potential to serve as alternative to commercial plastic. Bioplastics are gaining attention due to sustainability, biodegradability, biocompatibility, and lower carbon footprint. Nevertheless, the commercialization of PHA is predominantly hindered by the elevated production expenses arising primarily from the use of a pure sugar substrate. Our study has established a feasible method for bioplastic formation applying Pseudomonas putida MTCC 2475 and Solanum tuberosum periderm as a carbon source. To optimize the sugar yield response surface methodology was used, which released 69.34% ± 0.25% reducing sugar. PHA production experiments were performed in hydrolysate containing media as well as commercial sugar containing mineral salt media. After 48 h of fermentation of using this sugar, a biomass concentration of 2.19 gL-1, with a PHA production of 0.60 gL-1 (28.71% ± 0.55%) was obtained which was comparatively similar with synthetic media (2.56 gL-1 cell dry weight and 29.97% ± 0.45% PHA). Furthermore, the monomers of PHA produced by hydrolysate were characterized using Gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance. This investigation has identified three distinct monomers of medium-chain PHAs, namely, methyl 3-Hydroxydodecanoate, 3-Hydroxytetradecanoate, and Hexadecanoic acid 3-Hydroxy methyl esters. Hence this study concludes a sustainable production of bioplastics from S. tuberosum periderm waste.

Conversion of Corn Stover for Microbial Enzymes Production by Phanerochaete chrysosporium.

Phanerochaete chrysosporium, a white rot fungus, exhibits remarkable capabilities in producing various extracellular enzymes. These microbial enzymes find extensive applications in disrupting the intricate structure of plant cell walls, decolorizing synthetic dyes, and facilitating pulp extraction, among other functions. The process of solid-state fermentation stands out as an economical and sustainable approach, ideal for achieving high yields in enzyme production using lignocellulosic biomass as a substrate. In this research paper, both untreated and alkali pretreated corn stover materials served as substrates for enzyme production, leveraging the fungal strain's capacity to generate enzymes like cellulases and manganese peroxidase. The maximum production of endoglucanase was notably observed, reaching 121.21 ± 0.90 U/gds on the 9th day for untreated biomass and 79.75 ± 0.57 U/gds on the 6th day for treated biomass. Similarly, the peak exoglucanase production was recorded at 2.46 ± 0.008 FPU/ml on the 3rd day for untreated biomass and 0.92 ± 0.002 FPU/ml on the 6th day for treated biomass. Furthermore, the highest production of manganese peroxidase was achieved, with values of 5076.81 U/l on the 6th day for untreated biomass and 1127.58 ± 0.23 U/l on the 3rd day for treated biomass. These results collectively emphasize the potential of corn stover as a renewable and promising substrate for the production of essential enzymes.

Potato Peel Waste as an Economic Feedstock for PHA Production by Bacillus circulans.

Polymers of hydroxy alkanoates (PHA), also known as biodegradable, biocompatible plastic, are potential alternatives to petrochemical-based plastics. PHA is synthesized by microbes in their cytoplasm in the form of inclusion bodies in stress conditions such as nitrogen, oxygen, and phosphorus with excessive amounts of carbon. Sugar extracted from potato peel in the form of hydrolysate was employed as a carbon source for PHA production after acidic hydrolysis. The acid hydrolysis conditions are optimized for dilute acid concentrations and temperatures. The highest sugar-yielding condition (2% 15 min at 121 ℃) was used for submerged fermentation for PHA production by Bacillus circulans MTCC 8167. Fourier transform infrared spectroscopy, nuclear magnetic resonance, and differential scanning calorimetry were used for polymer characterization. Gas chromatography coupled with mass spectrometry confirmed the monomers such as hexadecenoic acid 3-hydroxy, methyl esters, pentadecanoic acid 14 methyl esters, and tetradecanoic acid 12- methyl esters. Crotonic acid assay was used for quantification of PHA and it was found highest (0.232 ± 0.04 g/L) at 37 °C and 36 h of incubation. Hence, potato peel waste could be a potential feedstock for waste to valuable production.

Potential of Rhodosporidium toruloides for Fatty Acids Production Using Lignocellulose Biomass.

Microbial lipids are ideal for developing liquid biofuels because of their sustainability and no dependence on food crops. Especially the bioprocess for microbial lipids may be made economical by using sustainable approaches, e.g., lignocellulose-based carbon sources. This demand led to a search for ideal microorganisms with the ability to utilize efficiently biomass into value-added products. Rhodosporidium toruloides species belongs to the family of oleaginous (OG) yeast, which aggregates up to 70% of its biomass to produce fatty acids which can be converted to a variety of biofuels. R. toruloides is extremely adaptable to different types of feedstocks. Among all feedstock, a lot of effort is going on to develop a bioprocess of fatty acid production from lignocellulose biomass. The lignocellulose biomass is pretreated using harsh conditions of acid, alkali, and other which leads to the generation of a variety of sugars and toxic compounds. Thus, so obtained lignocellulose hydrolysate may have conditions of different pH, variable carbon and nitrogen ratios, and other non-optimum conditions. Accordingly, a detailed investigation is required for molecular level metabolism of R. toruloides in response to the hydrolysate for producing desired biochemicals like fatty acids. The present review focuses on numerous elements and obstacles, including metabolism, biofuel production, cultivation parameters, and genetic alteration of mutants in extracting fatty acids from lignocellulosic materials utilizing Rhodosporidium spp. This review provides useful information on the research working to develop processes for lignocellulose biomass using oleaginous yeast.

Biofilm patterns in gram-positive and gram-negative bacteria.

The Gram-positive and Gram-negative bacteria are attributable to matrix-enclosed aggregates known as biofilms. Biofilms are root cause of industrial biofouling and characterized by antimicrobial resistance during infections. Many biofilm studies examine specific Gram type cultures, whereas nearly all biofilm communities in nature comprise both Gram-negative and Gram-positive bacteria. Thus, a greater understanding of the conserved themes in biofilm formation is required for common therapeutics. We tried to focus on common components which exist at each stage of biofilm development and regulation. The Lipopolysaccharides (LPS) and cell wall glyco-polymers of Gram-negative and Gram-positive bacteria seem to play similar roles during initial adhesion. The inhibition of the polymerization of amyloid-like proteins might impact the biofilms of both Gram-type bacteria. Enzymatic degradation of matrix components by glycoside hydrolase and DNase (nuclease) may disrupt both Gram-type biofilms. An additional common feature is the presence of membrane vesicles, and the potential of these vesicles requires further investigation. Genetic regulation by c-di-GMP is prominent in Gram-negative bacteria. However, quorum sensing (QS) may play a common regulation during biofilms dispersal. These studies are significant not only for common therapeutic against mixed biofilms, but for better understanding of bacterial interactions within natural or host infection environment as well.

Conversion of grass biomass into fermentable sugars and its utilization for medium chain length polyhydroxyalkanoate (mcl-PHA) production by Pseudomonas strains.

This study investigated the potential of grass biomass as a feedstock for mcl-PHA production. Pretreatments (2% NaOH at 120°C or hot water at 120°C) of perennial ryegrass were employed alone or in combination with sodium chlorite/acetic acid (SC/AA) delignification to evaluate the enzymatic digestibility and subsequent utilization of resultant sugars by Pseudomonas strains. NaOH pretreated sample had better digestibility than raw and hot water treated samples and this hydrolysate supported good growth of all tested strains with limited mcl-PHA (6-17% of cell dry mass (CDM)) accumulation. Digestibility of both untreated and pretreated samples was improved after SC/AA delignification and produced glucose (74-77%) rich hydrolysates. Tested strains accumulated 20-34% of CDM as PHA when these hydrolysates were used as sole carbon and energy source. CDM and PHA yields obtained for these strains when tested with laboratory grade sugars was similar to that achieved with grass derived sugars.

Trends in bacterial trehalose metabolism and significant nodes of metabolic pathway in the direction of trehalose accumulation.

The current knowledge of trehalose biosynthesis under stress conditions is incomplete and needs further research. Since trehalose finds industrial and pharmaceutical applications, enhanced accumulation of trehalose in bacteria seems advantageous for commercial production. Moreover, physiological role of trehalose is a key to generate stress resistant bacteria by metabolic engineering. Although trehalose biosynthesis requires few metabolites and enzyme reactions, it appears to have a more complex metabolic regulation. Trehalose biosynthesis in bacteria is known through three pathways--OtsAB, TreYZ and TreS. The interconnections of in vivo synthesis of trehalose, glycogen or maltose were most interesting to investigate in recent years. Further, enzymes at different nodes (glucose-6-P, glucose-1-P and NDP-glucose) of metabolic pathways influence enhancement of trehalose accumulation. Most of the study of trehalose biosynthesis was explored in medically significant Mycobacterium, research model Escherichia coli, industrially applicable Corynebacterium and food and probiotic interest Propionibacterium freudenreichii. Therefore, the present review dealt with the trehalose metabolism in these bacteria. In addition, an effort was made to recognize how enzymes at different nodes of metabolic pathway can influence trehalose accumulation.

Saccharification of Kans grass using enzyme mixture from Trichoderma reesei for bioethanol production.

Bioethanol is one of the alternatives of the conventional fossil fuel. In present study, effect of different carbon sources on the production of cellulolytic enzyme (CMCase) from Trichoderma reesei at different temperatures, duration and pH were investigated and conditions were optimized. Acid treated Kans grass (Saccharum sponteneum) was subjected to enzymatic hydrolysis to produce fermentable sugars which was then fermented to bioethanol using Saccharomyces cerevisiae. The maximum CMCase production was found to be 1.46 U mL(-1) at optimum condition (28°C, pH 5 and cellulose as carbon source). The cellulases and xylanase activity were found to be 1.12 FPU g(-1) and 6.63 U mL(-1), respectively. Maximum total sugar was found to be 69.08 mg/g dry biomass with 20 FPU g(-1) dry biomass of enzyme dosage under optimum condition. Similar results were obtained when it was treated with pure enzyme. Upon fermentation of enzymatic hydrolysate, the yield of ethanol was calculated to be 0.46 g g(-1).