Optimization of hydrothermal-assisted alkali process for enhanced xylan recovery from banana fiber biomass

Banana fiber is a rich lignocellulosic biomass source that has not been widely explored. The hemicellulose components (15 - 20 %) of banana fiber can be a feedstock for producing high-value commodity chemicals. Hemicellulose is extracted by physical, chemical, and biological methods, in which combining hydrothermal treatment with alkaline mode of extraction provides an enhanced recovery percentage. Thus, the present study aimed to optimize the hydrothermal-assisted alkaline method of xylan extraction from the banana fiber biomass. Initially, xylan was extracted with a conventional-based alkali method. A maximum of about 43 and 35 % was recovered from pretreated and raw banana fiber at 12% NaOH concentration when incubated at 55 °C for 24 h. To improve the xylan yield, the hydrothermal assisted alkali method experimented in which 67.1% and 58.3 % of xylan were recovered when treated at 121 °C for 1 h at 12% NaOH. To further enhance the xylan recovery, a two-step alkali process by combining conventional and hydrothermal-assisted alkali methods resulted in the highest xylan (81%) recovery from pretreated banana fiber when incubated with 12 % alkali for 8 h followed by steam treatment. On the other hand, a maximum of 73 % of xylan was recovered when steam treated after incubation for 24 h from raw banana fiber. Thus, the alkali incubation followed by steam treatment significantly showed the highest xylan recovery from the banana fiber biomass. The extracted xylan might be utilized as a source for various xylan-based products, including furfural, xylooligosaccharides, xylose, and xylitol, all of which have significant roles in the pharmaceutical and food industries

Evaluating the impact of an organic nitrification inhibitor on nitrogen availability and its influence on microbial population in paddy soil

An incubation study was conducted to estimate the potential inhibition rates of nitrification using phytonim-coated fertilizers like urea and ammonium sulfate (AS) at different concentrations viz., 100 % and 65 % of the recommended dosage (RD) and additionally ammonifying bacteria (AB) was added with urea as one of the treatments. Samples were taken at 13 different intervals in a 45-day incubation experiment. Applying phytonim-coated fertilizers delayed the nitrification process for 35 days, improving the soils' available N. Ammonia oxidation and nitrite oxidation rates were reduced by 14 % and 35 % in phytonim-coated urea, 11 % and 23 % in phytonim-coated urea + AB and 24 % and 45 % in phytonim-coated AS, respectively over uncoated fertilizers. Nitrate reductase activity was reduced by 17 %, 16 % and 21 % in phytonim-coated fertilizers like urea, AS and urea + AB compared to uncoated fertilizers. Soil urease activity was inhibited in phytonim-coated urea (100 % RD and 65 % RD) of 9.6 % and 7.4 %, respectively, whereas 5.7 % and 6.7 % increased urease activity were observed in phytonim-coated urea + AB (100 % RD) and coated urea + AB (65 % RD). Increased soil dehydrogenase activity and FDA hydrolysis of 20 % and 15 % were observed in phytonim-coated urea, 15 % and 18 % in phytonim-coated urea + AB (100 % RD) and 17 % and 16 % in phytonim-coated AS over uncoated fertilizers. Results show that phytonim-coated AS (100 % RD) (T8) has inhibited nitrification most, followed by phytonim-coated urea (100 % RD) (T4) during the incubation period. This study concludes that applying organic nitrification inhibitors inhibited the nitrification and denitrification rates, affected the urea hydrolysis and positively affected the microbial population

Bioactive Metabolites of Nodule Associated Microbes for Enhanced Drought Tolerance and Biocontrol Control Activity in Horsegram

In the present study, the potential bioactive compounds detected in the ethyl acetate microbial extract of root nodules of horsegram were determined using the gas chromatography-mass spectroscopy (GC-MS).  The bioactive metabolites of nodule associated microbes (NAM) revealed the existence of several soluble metabolites which includes phthalic acid, butyl hex-3-yl ester, 2,4-Di-tert-butylphenol,Dodecyl acrylate, pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro, 1-Nonadecene, octadecane, 1,2-Benzenedicarboxylic acid, bis(2-methylpropyl) ester, hexadecanoic acid, methyl ester, dibutyl phthalate, diisooctyl phthalate, 1-docosene, heptadecane, 9-hexyl, pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(phenylmethyl), n-Tetracosanol-1, ergotaman-3',6',18-trione, 9,10-dihydro-12'-hydroxy-2'-methyl-5'(phenylmethyl)-, (5'à,10à), eicosanal, ethanol, 2-(9-octadecenyloxy), E-15-heptadecenal, octatriacontyl pentafluoropropionate, etc.,.  Endophytic bacteria produces bioactive substances that provides resistance against phytopathogens as well as nutrient solubilization  during prolonged drought periods  in order to overcome biotic and abiotic stresses. Several antibacterial, antifungal, antiviral and antioxidant properties were brought under spotlight to realise the beneficial aspects of nodule associated microbes of horsegram. Understanding the roles of metabolites would enrich the crop growth under stressed environment by promoting the eco-friendly agriculture practices

Bioactive Metabolites of Nodule Associated Microbes for Enhanced Drought Tolerance and Biocontrol Control Activity in Horsegram

In the present study, the potential bioactive compounds detected in the ethyl acetate microbial extract of root nodules of horsegram were determined using the gas chromatography-mass spectroscopy (GC-MS).  The bioactive metabolites of nodule associated microbes (NAM) revealed the existence of several soluble metabolites which includes phthalic acid, butyl hex-3-yl ester, 2,4-Di-tert-butylphenol,Dodecyl acrylate, pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro, 1-Nonadecene, octadecane, 1,2-Benzenedicarboxylic acid, bis(2-methylpropyl) ester, hexadecanoic acid, methyl ester, dibutyl phthalate, diisooctyl phthalate, 1-docosene, heptadecane, 9-hexyl, pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(phenylmethyl), n-Tetracosanol-1, ergotaman-3',6',18-trione, 9,10-dihydro-12'-hydroxy-2'-methyl-5'(phenylmethyl)-, (5'à,10à), eicosanal, ethanol, 2-(9-octadecenyloxy), E-15-heptadecenal, octatriacontyl pentafluoropropionate, etc.,.  Endophytic bacteria produces bioactive substances that provides resistance against phytopathogens as well as nutrient solubilization  during prolonged drought periods  in order to overcome biotic and abiotic stresses. Several antibacterial, antifungal, antiviral and antioxidant properties were brought under spotlight to realise the beneficial aspects of nodule associated microbes of horsegram. Understanding the roles of metabolites would enrich the crop growth under stressed environment by promoting the eco-friendly agriculture practices.</jats:p

Plant growth promoting signatory volatiles emitted by a drought-tolerant bacterium Bacillus altitudinis FD48 and its role in moisture stress alleviation in rice (Oryza sativa L.)

Increasing evidence implies that bacterial volatile organic compounds (bVOCs) play a significant role in plant-microbe interaction. Plant associated bacteria produces plant growth modulating volatiles elicits induced systemic tolerance (IST) in plants against a multitude of abiotic stress. Induction of IST and plant growth promotion by signatory bVOCs of Bacillus altitudinis FD48 against drought are reported in this study. The rice seedlings exposed to bVOCs blends of FD48 showed a one-fold increase in whole plant biomass and auxin content (3 µmol g-1 FW) under induced moisture stress. The effect of bVOCs highly depends on the inoculum load. Higher inoculum quantity (100 µL) is detrimental to plant growth. bVOCs produced by FD48 profiled at different growth intervals in GC–MS-ATD revealed a total of 40 bioactive compounds both under stress (PEG 6000) and non-stressed conditions. Interestingly, potential plant growth-promoting compounds such as 1-Hexanol, 2,3-butanediol, dimethyl disulfide, benzene, butanoic acid, pentadecane, and acetic acid are more pronounced. Few compounds produced under non-stress were found to increase during stress (example, 2,3-Butanediol, and acetic acid). This study unraveled the significant biosynthetic pathways induced by FD48 bVOC blends, such as pyruvate metabolism, tryptophan metabolism, sulfur metabolism, fatty acid biosynthesis, and ethanol degradation that anchors in abating moisture stress. Hence, it can be concluded that PGPB B. altitudinis FD48 produced bVOCs could be potential orchestrators of induced systemic tolerance in plants against moisture stress

Physiological Adaptation and Plant Growth Promoting Functional Traits of Bacillus altitudinis FD48 under In vitro Osmotic Stress

To develop an osmotolerant microbe, as a bioinoculant to mitigate drought it is vital to understand the impact of osmotic stress on their growth and plant growth promoting functional traits. The present study was aimed to evaluate the physiological adaptations and plant growth-promoting traits of a phyllosphere bacterium Bacillus altitudinis FD48 under osmotic stress conditions. The FD48 strain isolated from rice (cultivar ADT43) phyllosphere obtained from Biocatalysts laboratory, Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore. In vitro bioassay was conducted to evaluate the osmotolerant potentials of FD48. B. altitudinis FD48 grown in LB supplemented with PEG 6000 and grown for 48 hrs. Physiological adaptation to osmotic stress was observed by assessing the osmolytes and free amino acids content produced by FD48 under induced stress. Further the plant growth promoting traits under osmotic stress also asceratined. The growth pattern of FD48 strain decreased with the increase in PEG concentrations. The lower level of osmotic stress enhanced the growth of FD48 but at higher concentration exhibited a decline in growth. Enhanced levels of IAA (25 µg g-1 of protein) and EPS (9.76 mg mg-1 protein) production were recorded in the FD48 strain at lower levels of osmotic stress. Furthermore, an increase in osmotic stress had a deleterious effect on IAA production and ACC deaminase activity while the exopolysaccharide production was enhanced. Growth of FD48 under osmotic stress also increased the accumulation of proline and compatible sugars that will protect the FD48 strain by maintaining the turgor potential of cells and stabilizes the membrane proteins. Hence, the results of our study suggesting that, B. altitudinis FD48 strain has the potential to tolerate osmotic stress and might be used as a newer bio-inoculant for triggering moisture deficit stress resilience in plants.</jats:p