An oxidant- and organic solvent-resistant alkaline metalloprotease from Streptomyces olivochromogenes

Purification and Characterization of a Small Thermostable Protease from Streptomyces sp. CNXK100

Proteases derived from Streptomyces demonstrate numerous commendable properties, rendering it extensively applicable in biotechnology and various industrial sectors. This study focused on the purification and characterization of the thermostable protease obtained from Streptomyces sp. CNXK100. The purified protease exhibited an estimated molecular weight of 27 kDa, with optimal activity at 75°C and pH 8.0. Notably, the enzyme remained active even without any metal ions and fully active in the presence of Na+, K+, Mg2+, and Cu2+metal ions. The kinetic parameters were determined with a KM value of 3.13 mg/ml and a Vmax value of 3.28 × 106 U/mg. Furthermore, the protease has demonstrated notable stability when subjected to a treatment temperature of up to 65°C for 60 minutes, and across a broad pH range extending from 5.0 to 10.0. This protease also demonstrated resilience against a spectrum of harsh conditions, including exposure to organic solvents, surfactants, bleaching agents, and proteolytic enzymes. Additionally, the enzyme maintained its activity following treatment with commercial detergents, accomplishing complete thrombus lysis at a concentration of 2.50 mg/ml within 4 hours. Remarkably, the protease exhibited stability in terms of activity and protein concentration for 70 days at 4°C. These findings underscore the potential industrial applications of the thermostable protease from Streptomyces sp. CNXK100.

Ultra-high throughput screening for novel protease specificities

The screening of large libraries of enzyme variants remains an essential tool in evolving biocatalysts toward improved properties for applications in medicine, chemistry, and a broad variety of other fields. Over the last decades, the technology for conducting systematic screens of arrayed members of a library of enzyme variants has made great strides in terms of increasing throughput and reducing assay volume. Here, we describe in detail an alternative to arrayed analysis, which is a screen based on density shifts in result of changed enzyme function, which allows highly parallelized screening. Specifically, we link changes in protease substrate specificity in vivo to the production of an alternative reporter protein, catalase. Depending on the catalase expression level, microcolonies of library bacteria with active protease variants contained in polymeric droplets generate an oxygen bubble, which causes a density shift in the droplet and enables it to float.

Microbial Proteases Applications

The use of chemicals around the globe in different industries has increased tremendously, affecting the health of people. The modern world intends to replace these noxious chemicals with environmental friendly products for the betterment of life on the planet. Establishing enzymatic processes in spite of chemical processes has been a prime objective of scientists. Various enzymes, specifically microbial proteases, are the most essentially used in different corporate sectors, such as textile, detergent, leather, feed, waste, and others. Proteases with respect to physiological and commercial roles hold a pivotal position. As they are performing synthetic and degradative functions, proteases are found ubiquitously, such as in plants, animals, and microbes. Among different producers of proteases, Bacillus sp. are mostly commercially exploited microbes for proteases. Proteases are successfully considered as an alternative to chemicals and an eco-friendly indicator for nature or the surroundings. The evolutionary relationship among acidic, neutral, and alkaline proteases has been analyzed based on their protein sequences, but there remains a lack of information that regulates the diversity in their specificity. Researchers are looking for microbial proteases as they can tolerate harsh conditions, ways to prevent autoproteolytic activity, stability in optimum pH, and substrate specificity. The current review focuses on the comparison among different proteases and the current problems faced during production and application at the industrial level. Deciphering these issues would enable us to promote microbial proteases economically and commercially around the world.

Purification and partial characterization of a low molecular fibrinolytic serine metalloprotease C142 from the culture supernatant of Bacillus subtilis C142

Novel serine metalloprotease-like enzyme, C142 was purified from the culture supernatant of Bacillus subtilis C142. The C142 was purified to homogeneity by a two-step procedure with a 20.7-fold increase in specific activity and 0.9% recovery. The molecular mass of C142 was approximately 23.5kDa based on SDS-PAGE. The N-terminal amino acid sequence of the first 21 amino acids of C142 was AQSVPYGISQIKAPALHSQGY. Its optimum pH, optimum temperature, pH stability, and thermal stability were pH 6, 40°C, pH 6-8, and 20-35°C, respectively. C142 was strongly inhibited by PMSF and EGTA, suggesting that C142 was a serine metalloprotease-like enzyme. C142 showed the highest specificity toward the substrate for t-PA. The apparent K_m, V_max, and K_cat values of C142 toward H-d-Ile-Pro-Arg-pNA were determined as 0.34mM, 0.25mmolmg^-1min^-1, and 46.83s^-1. C142 exhibited fibrinolytic activity, which is stronger than that of plasmin. C142 hydrolyzed Aα, and Bβ-chains of fibrinogen, but did not cleave γ-chains. C142 had antithrombotic effect in three animal models. C142 was devoid of hemorrhagic activity at a dose of 20,000FU/kg. Taken together, our results indicate that B. subtilis C142 produces a serine metalloprotease-like enzyme/fibrinolytic enzyme and this enzyme might be used as a new thrombolytic agent.

Partial Characterization of the Proteolytic Properties of an Enzymatic Extract From "Aguama" Bromelia pinguin L. Fruit Grown in Mexico

Plant proteases are capable of performing several functions in biological systems, and their use is attractive for biotechnological process due to their interesting catalytic properties. Bromelia pinguin (aguama) is a wild abundant natural resource in several regions of Central America and the Caribbean Islands but is underutilized. Their fruits are rich in proteases with properties that are still unknown, but they represent an attractive source of enzymes for biotechnological applications. Thus, the proteolytic activity in enzymatic crude extracts (CEs) from wild B. pinguin fruits was partially characterized. Enzymes in CEs showed high proteolytic activity at acid (pH 2.0-4.0) and neutral alkaline (pH 7.0-9.0) conditions, indicating that different types of active proteases are present. Proteolytic activity inhibition by the use of specific protease inhibitors indicated that aspartic, cysteine, and serine proteases are the main types of proteases present in CEs. Activity at pH 3.0 was stable in a broad range of temperatures (25-50 °C) and retained its activity in the presence of surfactants (SDS, Tween-80), reducing agents (DTT, 2-mercapoethanol), and organic solvents (methanol, ethanol, acetone, 2-propanol), which suggests that B. pinguin proteases are potential candidates for their application in brewing, detergent, and pharmaceutical industries.

A novel alkaline lipase from Ralstonia with potential application in biodiesel production

With the aim of isolating a biocatalyst able to catalyze biodiesel production from microbial source, Ralstonia sp. CS274 was isolated and a lipase from the strain (RL74) was purified. Molecular weight of RL74 was estimated to be 28,000 Da by SDS-PAGE. The activity was highest at 50-55°C and pH 8.0-9.5 and was stable at pH 7.0-12.0 and up to 45°C. It was resistant to oxidizing and reducing agents and the activity was enhanced by detergents. RL74 was 1,3 specific and K(m) and V(max) for p-nitrophenyl palmitate were 2.73 ± 0.6mM and 101.4 ± 1.9 mM/min mg, respectively. N-terminal amino acid sequence showed partial homology with that of Penicillium lipases. RL74 produced biodiesel more efficiently in palm oil than in soybean oil; and the production was highest at pH 8.0, at 5% methanol and at 20% water content.