Recovery of Bacillus licheniformis Alkaline Protease from Supernatant of Fermented Wastewater Sludge Using Ultrafiltration and Its Characterization

Integrated-Omics Study on the Transcriptomic and Metabolic Changes of Bacillus licheniformis, a Main Microorganism of Fermented Soybeans, According to Alkaline pH and Osmotic Stress

Bacillus licheniformis has been widely utilized in the food industry as well as various agricultural industries. In particular, it is a main microorganism of fermented soybeans. In this study, the changes of the metabolome and transcriptome of B. licheniformis KACC15844, which had been isolated from fermented soybeans, were investigated depending on alkaline pH (BP) and a high salt concentration (BS) using an integrated-omics technology, focusing on leucine metabolism. Overall, carbohydrate (glycolysis, sugar transport, and overflow) and amino acid (proline, glycine betaine, and serine) metabolisms were strongly associated with BS, while fatty acid metabolism, malate utilization, and branched-chain amino acid-derived volatiles were closely related to BP, in both gene and metabolic expressions. In particular, in leucine metabolism, the formation of 3-methylbutanoic acid, which has strong cheesy odor notes, was markedly increased in BP compared to the other samples. This study provided information on how specific culture conditions can affect gene expressions and metabolite formations in B. licheniformis using an integrated-omics approach.

Utilization of biosolids for glucose oxidase production: A potential bio-fenton reagent for advanced oxidation process for removal of pharmaceutically active compounds

The current work focuses on the production of glucose oxidase (GOD) in sterilized biosolid (BS) slurries containing BS and municipal wastewater effluent. Various parameters were optimized for maximizing the GOD production and the effects of biostimulation on GOD production was investigated by adding synthetic media components. The studies on inoculum characteristics at an inoculum age of 72 h and inoculum size of 20% (w/v) produced high GOD activities of around 6012 U/L in 25% (dw/v) BS media. Further, the effect of ultrasonication time was determined to release BS-bound GOD in order to maximize enzymes recovery. Using 1000 U/L of the BS-based GOD for 0.55 M glucose oxidation produced the maximum H₂O₂ concentration of 216 ppm. The produced H₂O₂ was utilized for bio-Fenton based advanced oxidation process for the partial removal of 15 pharmaceutically active compounds.

Optimization of aqueous enzymatic method for Camellia sinensis oil extraction and reuse of enzymes in the process

Aqueous enzymatic extraction of Camellia sinensis oil was studied. The results suggested that saponin removal pretreatment assisted by ultrasound was effective in decreasing emulsification and in enhancing the free oil recovery. After 70% isopropanol extraction for 30 min under ultrasound, the residue of C. sinensis seeds was further hydrolyzed with free cellulase and Alcalase for 5 h, and calcium ions were concurrently added during enzymatic hydrolysis (n_Ca²⁺: n_saponin = 1:2), and free oil recovery up to 94.14% was obtained. Separate immobilization and co-immobilization of Alcalase and cellulase were performed by alginate entrapment combined with glutaraldehyde crosslinking. Specific activity and recovery of activity for Alcalase and cellulase were acceptable. After immobilization, Alcalase and cellulase exhibited higher activity at a wider pH and temperature range. Reuse experiments of immobilized enzymes were conducted. The deactivation kinetics immobilized enzymes were simulated and half-life of immobilized enzyme was estimated. The results indicated that a magnetic supporter facilitated the recovery of immobilized enzymes from tea seed slurry, and that immobilized Alcalase and cellulase had good reusability.

Purification and biochemical characterization of a novel thermostable serine alkaline protease from Aeribacillus pallidus C10: a potential additive for detergents

An extracellular thermostable alkaline serine protease enzyme from Aeribacillus pallidus C10 (GenBank No: KC333049), was purified 4.85 and 17. 32-fold with a yield of 26.9 and 19.56%, respectively, through DE52 anion exchange and Probond affinity chromatography. The molecular mass of the enzyme was determined through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), with approximately 38.35 kDa. The enzyme exhibited optimum activity at pH 9 and at temperature 60 °C. It was determined that the enzyme had remained stable at the range of pH 7.0-10.0, and that it had preserved more than 80% of its activity at a broad temperature range (20-80 °C). The enzyme activity was found to retain more than 70% and 55% in the presence of organic solvents and commercial detergents, respectively. In addition, it was observed that the enzyme activity had increased in the presence of 5% SDS. KM and Vmax values were calculated as 0.197 mg/mL and 7.29 μmol.mL-1.min-1, respectively.

Systematic functional analysis and application of a cold-active serine protease from a novel Chryseobacterium sp

Psychrotolerant bacteria isolated from natural and artificially cold environments were screened for synthesis of cold-active protease. The strain IMDY showing the highest protease production at 5°C was selected and phylogenetic analysis revealed that IMDY as novel bacterium with Chryseobacterium soli(T) as its nearest neighbor. Classical optimization enhanced the protease production from 18U/mg to 26U/mg and the enzyme was found to be active at low temperature, activity enhanced by CaCl2, inhibited by PMSF, stable against NaCl, and its activity retained in the presence of surfactants, organic solvents and detergents. On testing, the meat tenderization, myofibril fragmentation, pH, and TBA values were favorable in IMDY-protease treated meat compared to control. SDS profiling and SEM analysis also showed tenderization in meat samples. Hence, this study proposes to consider the cold-active protease from Chryseobacterium sp. IMDY as a pertinent candidate to develop potential applications in food processing industry.

Assessment of protease activity in hydrolysed extracts from SSF of hair waste by and indigenous consortium of microorganisms

Hair wastes from the tannery industry were assessed for its suitability as substrates for protease production by solid-state fermentation (SSF) using a pilot-batch mode operation and anaerobically digested sludge as co-substrate. Maximum protease activity (52,230±1601 U g(-1) DM) was observed at the 14th day of SSF. Single step purification resulted in 2 fold purification with 74% of recovery by ultrafiltration with 10 kDa cut-off. The recovered enzyme was stable at a temperature of 30°C and pH 11; optimal conditions that were determined by a central composite full factorial experimental design. The enzyme activity was inhibited by phenylmethylsulfonyl fluoride, which indicates that it belongs to serine protease group. The remaining solid material after protease extraction could be easily stabilized to obtain a final good quality compost-like material as the final dynamic respiration index was lower than 1 g O2 kg(-1) OM h(-1). The lyophilized recovered enzymes were a good alternative in the process of cowhides dehairing with respect to the current chemical treatment, avoiding the production of solid wastes and highly polluted wastewaters. In conclusion, the entire process can be considered a low-cost sustainable technology for the dehairing process, closing the organic matter cycle in the form of value added product and a compost-like material from a waste.

Thermotolerant alkaline protease enzyme from Bacillus licheniformis A10: purification, characterization, effects of surfactants and organic solvents

In this study, the extracellular thermostable alkaline protease out of A10 strain was purified 1.38-fold with 9.44% efficiency through the ammonium sulfate precipitation-dialysis and DE52 anion exchange chromatography methods. The molecular weight of the enzyme in question along with sodium dodecyl sulfate-polyacrylamide gel electrophoresis was determined to be approximately 40.55 kDa, whereas the optimum pH and temperature ratings were identified as 9.0 and 70 °C, respectively. It was seen that the enzyme had remained stable between pH 7.5-10.5 range, protecting more than 90% of its activity in the wake of 1 h incubation at 60-70 °C. It was also observed that the enzyme enhanced its activity in the presence of Mg(2+), Mn(2+), K(+), while Fe(2+), Ni(2+), Zn(2+), Ag(+ )and Co(2+ ) decreased the activity. Ca(2+), however, did not cause any change in the activity. The enzyme was seen to have been totally inhibited by phenylmethylsulfonyl fluoride, therefore, proved to be a serine alkaline protease.