Optimal production and characterization of alkaline protease from newly isolated halotolerant Jeotgalicoccus sp

Utilizing immobilized recombinant serine alkaline protease from Bacillus safensis lab418 in wound healing: Gene cloning, heterologous expression, optimization, and characterization

Microbial proteases have proven their efficiency in various industrial applications; however, their application in accelerating the wound healing process has been inconsistent in previous studies. In this study, heterologous expression was used to obtain an over-yielding of the serine alkaline protease. The serine protease-encoding gene aprE was isolated from Bacillus safensis lab 418 and expressed in E. coli BL21 (DE3) using the pET28a (+) expression vector. The gene sequence was assigned the accession number OP610065 in the NCBI GenBank. The open reading frame of the recombinant protease (aprEsaf) was 383 amino acids, with a molecular weight of 35 kDa. The yield of aprEsaf increased to 300 U/mL compared with the native serine protease (SAFWD), with a maximum yield of 77.43 U/mL after optimization conditions. aprEsaf was immobilized on modified amine-functionalized films (MAFs). By comparing the biochemical characteristics of immobilized and free recombinant enzymes, the former exhibited distinctive biochemical characteristics: improved thermostability, alkaline stability over a wider pH range, and efficient reusability. The immobilized serine protease was effectively utilized to expedite wound healing. In conclusion, our study demonstrates the suitability of the immobilized recombinant serine protease for wound healing, suggesting that it is a viable alternative therapeutic agent for wound management.

Interaction analysis of tobacco leaf microbial community structure and volatiles flavor compounds during cigar stacking fermentation

Introduction

Cigar stacking fermentation is a key step in tobacco aroma enhancement and miscellaneous gas reduction, which both have a great influence on increasing cigar flavor and improving industrial availability.

Methods

To analyze the effect of cigar tobacco leaf (CTLs) microbial community on volatiles flavor compounds (VFCs), this study used multi-omics technology to reveal the changes in microbial community structure and VFCs of different cigar varieties during stacking fermentation, in addition to exploring the interaction mechanism of microbiome and VFCs.

Results

The results showed that the dominant microbial compositions of different CTL varieties during stacking fermentation were similar, which included Staphylococcus, Corynebacterium 1, Aerococcus, and Aspergillus. These dominant microbes mainly affected the microbial community structure and characteristic microorganisms of CTLs through microbial interactions, thereby influencing the transformation of VFCs. Characteristic microorganisms of different CTLs varieties such as Trichothecium, Trichosporon, Thioalkalicoccus and Jeotgalicoccus, were found to positively correlate with characteristic VFCs like megastigmatrienone 4, pyrazine, tetramethyl-, geranyl acetone, and 2-undecanone, 6,10-dimethyl-, respectively. This in turn affected the aroma and sensory quality of the CTLs.

Discussion

This study provides theoretical support for the analysis of the mechanism of microorganisms on VFCs and aroma, and development of microbial agents during cigar stacking fermentation.

Bacillales: From Taxonomy to Biotechnological and Industrial Perspectives

For a long time, the genus Bacillus has been known and considered among the most applicable genera in several fields. Recent taxonomical developments resulted in the identification of more species in Bacillus-related genera, particularly in the order Bacillales (earlier heterotypic synonym: Caryophanales), with potential application for biotechnological and industrial purposes such as biofuels, bioactive agents, biopolymers, and enzymes. Therefore, a thorough understanding of the taxonomy, growth requirements and physiology, genomics, and metabolic pathways in the highly diverse bacterial order, Bacillales, will facilitate a more robust designing and sustainable production of strain lines relevant to a circular economy. This paper is focused principally on less-known genera and their potential in the order Bacillales for promising applications in the industry and addresses the taxonomical complexities of this order. Moreover, it emphasizes the biotechnological usage of some engineered strains of the order Bacillales. The elucidation of novel taxa, their metabolic pathways, and growth conditions would make it possible to drive industrial processes toward an upgraded functionality based on the microbial nature.

Biosynthesis and Characterization of a Novel Fibrinolytic Alkaline Serine Protease from Newly Isolated Bacillus flexus BF12 for Biomedical Applications

BACKGROUND

Cardiovascular Diseases (CVDs) such as stroke, high blood pressure, peripheral vascular disease, ischemic heart disease and acute myocardial infarction are some of the leading causes of death. To treat CVDs, commercially available thrombolytic agents are widely used. However, these thrombolytic agents have various side effects. Alternatively, fibrinolytic enzymes from bacterial sources are highly safe and have direct blood clot lytic activity.

METHODS

A fibrinolytic enzyme producing bacterial strain, Bacillus flexus BF12, was isolated from a solar saltpan in Kanyakumari District, Tamilnadu, India. Enzyme production was improved by optimizing physical factors and nutritional factors.

RESULTS

A novel fibrinolytic enzyme was isolated from a strain of the studied B. flexus BF12. Enzyme production was enhanced significantly by optimizing process parameters. The critical physical factors (pH and salinity) and influencing nutritional factors (carbon, nitrogen and ions) were optimized by one variable at a time approach, followed by the statistical method. The strain BF12 was highly active at alkaline pH (>7.0) and between 4 and 6% NaCl concentration. The nutrients such as fructose (carbon source), beef extract (nitrogen source) and CaCl₂ significantly influenced enzyme production. Central composite design and response surface methodology improved 3.2-fold enzyme yield than unoptimized culture medium. Fibrinolytic protease was purified by ammonium sulphate precipitation, dialysis and gel filtration chromatography.

DISCUSSION

The molecular weight of an enzyme was found to be 23 kDa. It was active at a broad temperature (40-60 °C) and pH (7.0-9.0) ranges. Enzyme activity was enhanced by Ca²⁺ and Co²⁺ ions. The purified protease retained 100% enzyme activity in the presence of ethanol and acetone. Acetonitrile, butanol, DMSO, methanol and chloroform showed enzyme activity of 63%, 92.5%, 94.7%, 92.3% and 90.4%, respectively. The purified enzyme degraded 100% of human blood clot.

CONCLUSION

The Bacillus flexus BF12 fibrinolytic enzyme shows promising potentials in nutraceutical and food fortification applications. The application of fibrinolytic enzymes could prevent CVDs.

Enhanced catalytic activity of Bacillus aryabhattai P1 protease by modulation with nanoactivator

In the developing area of modern nanobiotechnology, the research is being focused on enhancement of catalytic performance in terms of efficiency and stability of enzymes to fulfill the industrial demand. In the context of this interdisciplinary era, we isolated and identified alkaline protease producer Bacillus aryabhattai P1 by polyphasic approach and then followed one variable at a time approach to optimize protease production from P1. The modified components of fermentation medium (g/L) were wheat bran 10, soybean flour 10, yeast extract 5, NaCl 10, KH₂PO₄ 1, K₂HPO₄ 1 and MgSO₄·7H₂O 0.2 (pH 9). The optimum alkaline protease production from P1 was recorded 75 ± 3 U/mg at 35 °C and pH 9 after 96 h of fermentation period. Molecular weight of partially purified P1 alkaline protease was 26 KDa as revealed by SDS-PAGE. Calcium based nanoceramic material was prepared by wet chemical precipitation method and doped in native P1 protease for catalytic activity enhancement. Catalytic activity of modified P1 protease was attained by nanoactivator mediated modulation was more by 5.58 fold at pH 10 and 30 °C temperature. The nanoceramic material named as nanoactivator, with grain size of 40–60 nm was suitable to redesign the active site of P1 protease. Such types of modified proteases can be used in different nanobiotechnological applications.

Optimization of Parameters that Affect the Activity of the Alkaline Protease from Halotolerant Bacterium, Bacillus acquimaris VITP4, by the Application of Response Surface Methodology and Evaluation of the Storage Stability of the Enzyme

BACKGROUND

It was previously shown that the activity of a serine protease from a moderately halotolerant Bacillus aquimaris VITP4 strain is active in a wide range of pH and temperatures and could be modulated by the presence of the divalent metal ions.

OBJECTIVES

In the present study, a quantitative analysis was done in order to explore the parameters that are contributing to the protease activity.

MATERIALS AND METHODS

Changes in the secondary structure of the enzyme was determined by circular dichroism analysis. The conditions for the optimal activity was investigated by Response Surface Methodology. Stability of the enzyme was determined by thermal inactivation experiments.

RESULTS

The initial one-factor-at-a-time experiments have indicated that the activity of the enzyme could be enhanced not only by the presence of low concentrations of NaCl but also by divalent metal ions, such as Ca²⁺, Mn²⁺ and Cu²⁺. A clear dependence of the activity to the secondary structure of the enzyme could be established using circular dichroism spectroscopy. In the next level of optimization, four factors; viz. pH, temperature, concentration of Ca2+, and Mn²⁺ were used to optimize the conditions required for the maximal activity of the enzyme by Response Surface Methodology, and the data could be explained using quadratic model. Under optimal condition of 43°C, pH 8.0, 8.2 mM Ca²⁺, and 4.3 mM Mn²⁺ a 1.5 times enhancement in the enzyme activity could be achieved. The storage stability of the enzyme under these selected conditions has indicated a non-linear relation between the conditions for the enzymatic activity as well as stability. However, the condition for the maximal stability (267±18 min) has corresponded to that of the optimal conditions for the maximal activity.

CONCLUSIONS

This study, for the first time, has explored the possibility of using statistical methods for identifying the optimal conditions for alkaline protease activity isolated from the halotolerant Bacillus aquimaris VITP4.

Enhancement of Alkaline Protease Activity and Stability via Covalent Immobilization onto Hollow Core-Mesoporous Shell Silica Nanospheres

The stability and reusability of soluble enzymes are of major concerns, which limit their industrial applications. Herein, alkaline protease from Bacillus sp. NPST-AK15 was immobilized onto hollow core-mesoporous shell silica (HCMSS) nanospheres. Subsequently, the properties of immobilized proteases were evaluated. Non-, ethane- and amino-functionalized HCMSS nanospheres were synthesized and characterized. NPST-AK15 was immobilized onto the synthesized nano-supports by physical and covalent immobilization approaches. However, protease immobilization by covalent attachment onto the activated HCMSS–NH₂ nanospheres showed highest immobilization yield (75.6%) and loading capacity (88.1 μg protein/mg carrier) and was applied in the further studies. In comparison to free enzyme, the covalently immobilized protease exhibited a slight shift in the optimal pH from 10.5 to 11.0, respectively. The optimum temperature for catalytic activity of both free and immobilized enzyme was seen at 60 °C. However, while the free enzyme was completely inactivated when treated at 60 °C for 1 h the immobilized enzyme still retained 63.6% of its initial activity. The immobilized protease showed higher V_max, k_cat and k_cat/K_m, than soluble enzyme by 1.6-, 1.6- and 2.4-fold, respectively. In addition, the immobilized protease affinity to the substrate increased by about 1.5-fold. Furthermore, the enzyme stability in various organic solvents was significantly enhanced upon immobilization. Interestingly, the immobilized enzyme exhibited much higher stability in several commercial detergents including OMO, Tide, Ariel, Bonux and Xra by up to 5.2-fold. Finally, the immobilized protease maintained significant catalytic efficiency for twelve consecutive reaction cycles. These results suggest the effectiveness of the developed nanobiocatalyst as a candidate for detergent formulation and peptide synthesis in non-aqueous media.

Production, Purification, and Biochemical Characterization of Thermostable Metallo-Protease from Novel Bacillus alkalitelluris TWI3 Isolated from Tannery Waste

Protease enzymes in tannery industries have enormous applications. Seeking a potential candidate for efficient protease production has emerged in recent years. In our study, we sought to isolate proteolytic bacteria from tannery waste dumping site in Tamilnadu, India. Novel proteolytic Bacillus alkalitelluris TWI3 was isolated and tested for protease production. Maximum protease production was achieved using lactose and skim milk as a carbon and nitrogen source, respectively, and optimum growth temperature was found to be 40 °C at pH 8. Protease enzyme was purified using ammonium sulfate precipitation method and anion exchange chromatography. Diethylaminoethanol (DEAE) column chromatography and Sephadex G-100 chromatography yielded an overall 4.92-fold and 7.19-fold purification, respectively. The 42.6-kDa TWI3 protease was characterized as alkaline metallo-protease and stable up to 60 °C and pH 10. Ca(2+), Mn(2+), and Mg(2+) ions activated the protease, while Hg(2+), Cu(2+), Zn(2+), and Fe(2+) greatly inhibited it. Ethylenediaminetetraacetic acid (EDTA) inhibited TWI3 protease and was activated by Ca(2+), which confirmed that TWI3 protease is a metallo-protease. Moreover, this protease is capable of dehairing goat skin and also removed several cloth stains, which makes it more suitable for various biotechnological applications.