RESUMEN
In the present investigation, xylooligosaccharides were produced from wheat bran and wheat bran extracted xylan through enzymatic hydrolysis using xylanase from novel Enterobacter hormaechei KS1. Xylooligosaccharides/reducing sugars production from wheat bran was found maximum (374 mg/g) when 4.0% of wheat bran was treated with 375 units (IU/mL) of Enterobacter hormaechei KS1 xylanase at pH 6.0 and incubated at 50 °C for 24 h of incubation. In case of wheat bran extracted xylan 419 mg/g of xylooligosaccharides were produced when 3% of extracted xylan was incubate for 8 h. Analysis of the enzymatic hydrolysate through high performance liquid chromatography equipped with refractive index detector showed the presence of xylose, xylopentose and xylohexose. The decrease in pH with 1.0% dose of xylooligosacchaides produced from extracted xylan hydrolysis using E. hormaechei KS1 xylanase showed more decrease with L. rhamnosus (6.72 to 5.94) followed by L. brevis (6.71 to 6.15) and L. plantarum (6.71 to 6.41). In case of increase in optical density both wheat bran and wheat bran extracted xylan generated xylooligosaccharides exhibited similar pattern i.e., L. rhamnosus > L. plantarum > L. brevis.
RESUMEN
The effect of synthesised IONPs employing a nontoxic leaf extract of Azadirachta indica as a reducing, capping, and stabilizing agent for increasing biogas and methane output from cattle manure during anaerobic digestion (AD) was investigated in this study. Furthermore, the UV-visible spectra examination of the synthesized nanoparticles revealed a high peak at 432 nm. Using a transmission electron microscope, the average particle size of IONPs observed was 30-80 nm, with irregular, ultra-small, semi-spherical shapes that were slightly aggregated and well-distributed. IONPs had a polydisparity index (PDI) of 219 nm and a zeta potential of -27.0 mV. A set of six bio-digesters were fabricated and tested to see how varying concentrations of IONPs (9, 12, 15, 18, and 21 mg/L) influenced biogas, methane output, and effluent chemical composition from AD at mesophilic temperatures (35 ± 2 °C). With 18 mg/L IONPs, the maximum specific biogas and methane production were 136.74 L/g of volatile solids (VS) and 64.5%, respectively, compared to the control (p < 0.05), which provided only 107.09 L/g and 51.4%, respectively. Biogas and methane production increased by 27.6% and 25.4%, respectively using 18 mg/L IONPs as compared to control. In all treatments, the pH of the effluent was increased, while total volatile fatty acids, total solids, volatile solids, organic carbon content, and dehydrogenase activity decreased. Total solid degradation was highest (43.1%) in cattle manure + 18 mg/L IONPs (T5). According to the results, the IONPs enhanced the yield of biogas and methane when compared with controls.
RESUMEN
Heavy metal pollution in soil and water is a potential threat to human health as it renders food quality substandard. Different biosorbents such as microbial and agricultural biomass have been exploited for heavy metal immobilization in soil and sorptive removal in waters. Biosorption is an effective and sustainable method for heavy metal removal in soil and water, but the inherent challenges are to find cheap, selective, robust, and cost-effective bioadsorbents. Microbial and agricultural biomass and their modified forms such as nanocomposites and carbonaceous materials (viz., biochar, nanobiochar, biocarbon), might be useful for sequestration of heavy metals in soil via adsorption, ion exchange, complexation, precipitation, and enzymatic transformation mechanisms. In this review, potential biosorbents and their metal removal capacity in soil and water are discussed. The microbial adsorbents and modified composites of agricultural biomasses show improved performance, stability, reusability, and effectively immobilize heavy metals from soil and water. In the future, researchers may consider the modified composites, encapsulated biosorbents for soil and water remediation.
