Production of Alkaline Proteases using Aspergillus sp. Isolated from Injera: RSM-GA Based Process Optimization and Enzyme Kinetics Aspect

Release of CM-12 from A2-type casein by the cleavage of Ser-Leu-Xaa at the C-terminus using Aspergillus oryzae alkaline protease

BACKGROUND

Aspergillus oryzae protease can release the opioid peptide β-casomorphin-10 (CM-10, YPFPGPIPNS, 60-69) from A2-type casein. However, not only is the yield of the active peptide low, but the key enzyme involved in processing has yet to be identified.

RESULTS

A significant amount of the opioid peptide 60YPFPGPIPNSLP71 (CM-12) was produced from the A2-type casein peptide 53AQTQSLVYPFPGPIPNSLPQNIPPLTQTPV82 when the active protease in A. oryzae protease extract was fractionated with DEAE-Sepharose. The fractionated enzyme produced CM-12 from bovine A2-type casein but not from bovine A1 casein. A major protein of 34 kDa was purified and identified as an alkaline protease (Alp). Motif prediction of the Alp cleavage site using Multiple EM for Motif Elicitation analysis revealed preferable cleavage at the C-terminal end of Ser-Leu-Xaa for the release of CM-12. A2-type casein hydrolysate by Alp exhibited similar levels of opioid activity to that of synthetic CM-12 in cAMP-Glo assays with μ-opioid receptor-expressing HEK293 cells. These results suggest that CM-12 is a major opioid peptide in the casein hydrolysate.

CONCLUSION

Our findings showed that Alp fractionated from A. oryzae protease extract produced the opioid peptide CM-12 from A2-type casein as a result of preferential cleavage at the C-terminal end of Ser-Leu-Xaa and the removal of coexisting enzymes. Moreover, docking predictions suggested a stable interaction between CM-12 and the 3D structure of Alp. Casein hydrolysate with Alp-containing CM-12 has the potential for use as a bioactive peptide material with opioid activity. © 2024 Society of Chemical Industry.

Optimizing liquid fermentation for Wolfiporia cocos: gene expression and biosynthesis of pachymic acid and mycelial biomass

Wolfiporia cocos, a versatile fungus acclaimed for its nutritional and therapeutic benefits in Traditional Chinese Medicine, holds immense potential for pharmaceutical and industrial applications. In this study, we aimed to optimize liquid fermentation techniques and culture medium composition to maximize mycelial biomass (MB) yield, pachymic acid (PA) concentration, and overall PA production. Additionally, we investigated the molecular basis of our findings by quantifying the expression levels of genes associated with PA and MB biosynthesis using quantitative real-time polymerase chain reaction. Under the optimized fermentation conditions, significant results were achieved, with maximum MB reaching 6.68 g l-1, PA content peaking at 1.25 mg g-1, and a total PA yield of 4.76 g l-1. Notably, among the four examined genes, squalene monooxygenase, exhibited enhanced expression at 0.06 ratio under the optimized conditions. Furthermore, within the realm of carbohydrate-active enzymes, the glycoside hydrolases 16 family displayed elevated expression levels at 21 ratios, particularly during MB production. This study enhances understanding of genetic mechanism governing MB and PA production in W. cocos, highlighting the roles of squalene monooxygenase and glycoside hydrolases 16 carbohydrate-active enzymes.

Screening of cellulose-degrading bacteria and optimization of cellulase production from Bacillus cereus A49 through response surface methodology

Cellulose-degrading microorganisms hold immense significance in utilizing cellulose resources efficiently. The screening of natural cellulase bacteria and the optimization of fermentation conditions are the hot spots of research. This study meticulously screened cellulose-degrading bacteria from mixed soil samples adopting a multi-step approach, encompassing preliminary culture medium screening, Congo red medium-based re-screening, and quantification of cellulase activity across various strains. Particularly, three robust cellulase-producing strains were identified: A24 (MT740356.1 Brevibacillus borstelensis), A49 (MT740358.1 Bacillus cereus), and A61 (MT740357.1 Paenibacillus sp.). For subsequent cultivation experiments, the growth curves of the three obtained isolates were monitored diligently. Additionally, optimal CMCase production conditions were determined, keeping CMCase activity as a key metric, through a series of single-factor experiments: agitation speed, cultivation temperature, unit medium concentration, and inoculum volume. Maximum CMCase production was observed at 150 rpm/37 °C, doubling the unit medium addition, and a 5 mL inoculation volume. Further optimization was conducted using the selected isolate A49 employing response surface methodology. The software model recommended a 2.21fold unit medium addition, 36.11 °C temperature, and 4.91 mL inoculant volume for optimal CMCase production. Consequently, three parallel experiments were conducted based on predicted conditions consistently yielding an average CMCase production activity of 15.63 U/mL, closely aligning with the predicted value of 16.41 U/mL. These findings validated the reliability of the model and demonstrated the effectiveness of optimized CMCase production conditions for isolate A49.

Fungal alkaline proteases and their potential applications in different industries

The consumption of various enzymes in industrial applications around the world has increased immensely. Nowadays, industries are more focused on incorporating microbial enzymes in multiple processes to avoid the hazardous effects of chemicals. Among these commercially exploited enzymes, proteases are the most abundantly used enzymes in different industries. Numerous bacterial alkaline proteases have been studied widely and are commercially available; however, fungi exhibit a broader variety of proteases than bacteria. Additionally, since fungi are often recognized as generally regarded as safe (GRAS), using them as enzyme producers is safer than using bacteria. Fungal alkaline proteases are appealing models for industrial use because of their distinct spectrum of action and enormous diversity in terms of being active under alkaline range of pH. Unlike bacteria, fungi are less studied for alkaline protease production. Moreover, group of fungi growing at alkaline pH has remained unexplored for their capability for the production of commercially valuable products that are stable at alkaline pH. The current review focuses on the detailed classification of proteases, the production of alkaline proteases from different fungi by fermentation (submerged and solid–state), and their potential applications in detergent, leather, food, pharmaceutical industries along with their important role in silk degumming, waste management and silver recovery processes. Furthermore, the promising role of alkali–tolerant and alkaliphilic fungi in enzyme production has been discussed briefly. This will highlight the need for more research on fungi growing at alkaline pH and their biotechnological potential.

Unconventional microbial proteases as promising tools for the production of bioactive protein hydrolysates

Enzymatic hydrolysis is the most prominent strategy to release bioactive peptides from different food proteins and protein-rich by-products. Unconventional microbial proteases (UMPs) have gaining increased attention for such purposes, particularly from the 2010s. In this review, we present and discuss aspects related to UMPs production, and their use to obtain bioactive protein hydrolysates. Antioxidant and anti-hypertensive potentials, commonly evaluated through in vitro testing, are mainly reported. The in vivo bioactivities of protein hydrolysates and peptides produced through UMPs action are highlighted. In addition to bioactivities, enzymatic hydrolysis acts by modulating the functional properties of proteins for potential food uses. The compiled literature indicates that UMPs are promising biocatalysts to generate bioactive protein hydrolysates, adding up to commercially available enzymes. From the recent interest on this topic, continuous and in-depth research is needed to advance toward the applicability and commercial utility of both UMPs and obtained hydrolysates.

Characterization and rank assignment criteria for the anaerobic fungi (Neocallimastigomycota)

Establishing a solid taxonomic framework is crucial for enabling discovery and documentation efforts. This ensures effective communication between scientists as well as reproducibility of results between laboratories, and facilitates the exchange and preservation of biological material. Such framework can only be achieved by establishing clear criteria for taxa characterization and rank assignment. Within the anaerobic fungi (phylum Neocallimastigomycota), the need for such criteria is especially vital. Difficulties associated with their isolation, maintenance and long-term storage often result in limited availability and loss of previously described taxa. To this end, we provide here a list of morphological, microscopic, phylogenetic and phenotypic criteria for assessment and documentation when characterizing newly obtained Neocallimastigomycota isolates. We also recommend a polyphasic rank-assignment scheme for novel genus-, species- and strain-level designations for newly obtained Neocallimastigomycota isolates.

Adsorptive Capacity of Calcinated Hen Eggshell Blended with Silica Gel for Removal of Lead II Ions from Aqueous Media: Kinetics and Equilibrium Studies

In this study, a description was given for the adsorbent CaSiO₃ for allure proximate examination and determination like particle density, main part density, and porosity analysis. This is performed before management of batch adsorption experiments. Both kinetics and balance studies for the adsorbent were examined. The influences of various process parameters like lead concentration, pH, adsorbent dosage, and contact temporal length for process removal were explored. The removal efficiency of CaO from eggshell was enhanced to increase after mixing it with silica coagulate compared with added scholar's findings for the same limit. The maximum removal efficiency (99.58%) was obtained by limiting the pH, adsorbent dosage, initial lead concentration, and contact time at 4, 1.8 g, 35 g/L, and 140 minutes, respectively. Thus, blending CaO from eggshells with silica gel can increase the adsorption competency of CaO. Lead removal is well integrated into the Langmuir isotherm model with an equivalent factor of 0.991. The kinetic data of adsorption fit well into a pseudo-first-order model with a correlation coefficient of 0.90111. The pseudo-second-order model was the rate-determining step involved in the lead adsorption process for calcium silicate (CaSiO₃) adsorbents.

Comparison Study on Sonodirect and Sonoalternate Current Electrocoagulation Process for Domestic Wastewater Treatment

Nowadays, there is a problem related to wastewater handling which is released from different activities. The electrocoagulation method has been a dominant treatment method for wastewater treatment. There are different forms of electrocoagulation methods for wastewater treatment. Nevertheless, there was no comparison made for the removal efficiency of the sonoalternate current (SAC), alternate current (AC), sonodirect current (SDC), and direct current (DC) electrocoagulation process. The efficiency of electrocoagulation methods was compared for their removal of chemical oxygen demand (COD) from Jimma University domestic wastewater. Batch Reactor DC/AC electrocoagulation cell was used to determine the removal efficiency. During the comparison, the response surface methodology (RSM) was used to analyze and optimize the data taken from the laboratory. Besides, ANOVA was used to analyze the interaction effects of different parameters. The removal of COD from domestic wastewater was achieved with DCE, ACE, SDCE, and SACE which were 82.6%, 86.58%, 88.6%, and 92.5%, respectively, under optimal experimental conditions. From the finding, SACE was more successful at removing % COD than the DCE, ACE, and SDCE methods. For DCE and SDCE, the formation of an impermeable oxide layer at the cathode and the occurrence of corrosion at the anode due to oxidation made the COD removal process less efficient compared with SACE processes. From the experimental results it can be concluded that the SACE has the lowest power consumption and higher process efficiency than the other EC methods and can be a promising solution for removing pollutants from domestic wastewater.

Production and Optimization of Bio-Based Silica Nanoparticle from Teff Straw (Eragrostis tef) Using RSM-Based Modeling, Characterization Aspects, and Adsorption Efficacy of Methyl Orange Dye

The brown teff straw was utilized in this study to produce silica using the sol-gel technique. After pretreatment, the raw material of brown teff straw was characterized. The data were analyzed using the central composite design and response surface technique, and four independent parameters, namely, temperature, NaOH concentration, rotational speed, and extraction time, were evaluated for process optimization. Before extracting silica with an alkaline solution, the silica content in the ash was determined using an AAS spectrometer. The silica content of teff straw ash is around 92.89%. The ash was treated with NaOH solution in the concentrations range of 1 M to 3 M (0.5 M interval). The extraction time varied at intervals of 55, 70, 85, 100, and 115 minutes. Temperatures were changed using magnetic stirrer equipment in the range of 80°C to 100°C (5°C interval). At 350 rpm, 400 rpm, 450 rpm, 500 rpm, and 550 rpm, the rotating speed was adjusted. The best extraction conditions for amorphous silica were 1.50 M NaOH, 109.99 min, 94.98°C, and a rotating speed of 499.57 rpm, with a maximum yield of 85.85%. XRD and FTIR analyses were used to assess the physicochemical characteristics of the extracted silica. The aqueous solutions of methyl orange were used to test the adsorption efficiency of silica. The percent of removal efficiency for methyl orange was 90.48%.

A Statistical Modeling and Optimization for Cr(VI) Adsorption from Aqueous Media via Teff Straw-Based Activated Carbon: Isotherm, Kinetics, and Thermodynamic Studies

Currently, the growth of tannery industries causes a significant volume of waste disposal to the environment due to harmful Cr(VI). Long-time exposure to Cr(VI) imposes serious hazards on all living organisms. Hence, the treatment of tannery waste to remove Cr(VI) is not a choice but mandatory. Therefore, this study focused on the removal of Cr(VI) from the aqueous solutions via a teff (Eragrostis tef) straw based-activated carbon (TSAC) which was derived from locally available agricultural solid waste, teff straw (TS). The prepared TSAC was characterized using BET, FTIR, SEM, and XRD. A central composite approach-based RSM analysis was undertaken for statistical modeling and optimization for maximized Cr(VI) removal with respect to four important factors, namely, initial concentration of Cr(VI), the dosage of TSAC, pH, and adsorption time. Optimized values for maximizing adsorption of Cr(VI) (95% of removal) were acquired to be initial Cr(VI) concentration: 87.57 mg/L, TSAC dosage: 2.742 g/100 mL, pH: 2.2, and contact time:109 min. The results from the design of the experiment were also analyzed for the significance of the interaction between the selected process parameters. In addition, the pseudo-second-order kinetic and Langmuir isotherm models were found suitable for describing the adsorption data. The adsorption capacity of Cr(VI) on TSAC was 19.48 mg/g. The observed thermodynamic characteristics reveal that Cr(VI) adsorption on TASC is endothermic in nature. From the results, TSAC had shown a potential Cr(VI) efficiency on optimized process conditions that can be exploited effectively as adsorbent for removal of Cr(VI)-contaminated wastes.