Production, purification and characterisation of proteases from whey by some fungi

Insights into the mechanism of extracellular proteases from Penicillium on myofibrillar protein hydrolysis and volatile compound evolutions

To investigate the mechanism of Penicillium proteases on the hydrolysis of myofibrillar protein (MP) and volatile compound evolutions, enzymatic characteristics of Penicillium proteases, hydrolysis capacities for MP, interactions between Penicillium proteases and MP, and profile changes of volatile compounds were investigated. P. aethiopicum (PA) and P. chrysogenum (PC) proteases showed the largest hydrolysis activities at pH 9.0 and 7.0, and were identified as alkaline serine protease and serine protease by LC-MS/MS, respectively. The proteases of PA and PC significantly degraded myosin and actin, and PA protease showed higher hydrolysis capacity for myosin than that of PC protease, which was confirmed by higher proteolysis index (56.06 %) and lower roughness (3.99 nm) of MP after PA treatment. Molecular docking revealed that hydrogen bond and hydrophobic interaction were the major interaction forces of Penicillium proteases with myosin and actin, and PA protease showed more binding sites with myosin compared with PC protease. The total content of free amino acids increased to 6.02-fold for PA treatment and to 5.51-fold for PC treatment after 4 h hydrolysis of MP, respectively. GC-MS showed that aromatic aldehydes and pyrazines in PA showed the largest increase compared with the control and PC during the hydrolysis of MP. Correlation analysis demonstrated that Phe, Leu and Ile were positively related with the accumulation of benzaldehyde, benzeneacetaldehyde, 2,4-dimethyl benzaldehyde and 2,5-dimethyl pyrazine.

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.

Potential utilization of dairy industries by-products and wastes through microbial processes: A critical review

The dairy industry generates excessive amounts of waste and by-products while it gives a wide range of dairy products. Alternative biotechnological uses of these wastes need to be determined to aerobic and anaerobic treatment systems due to their high chemical oxygen demand (COD) levels and rich nutrient (lactose, protein and fat) contents. This work presents a critical review on the fermentation-engineering aspects based on defining the effective use of dairy effluents in the production of various microbial products such as biofuel, enzyme, organic acid, polymer, biomass production, etc. In addition to microbial processes, techno-economic analyses to the integration of some microbial products into the biorefinery and feasibility of the related processes have been presented. Overall, the inclusion of dairy wastes into the designed microbial processes seems also promising for commercial approaches. Especially the digestion of dairy wastes with cow manure and/or different substrates will provide a positive net present value (NPV) and a payback period (PBP) less than 10 years to the plant in terms of biogas production.

A Comprehensive Insight into Fungal Enzymes: Structure, Classification, and Their Role in Mankind's Challenges

Enzymes have played a crucial role in mankind's challenges to use different types of biological systems for a diversity of applications. They are proteins that break down and convert complicated compounds to produce simple products. Fungal enzymes are compatible, efficient, and proper products for many uses in medicinal requests, industrial processing, bioremediation purposes, and agricultural applications. Fungal enzymes have appropriate stability to give manufactured products suitable shelf life, affordable cost, and approved demands. Fungal enzymes have been used from ancient times to today in many industries, including baking, brewing, cheese making, antibiotics production, and commodities manufacturing, such as linen and leather. Furthermore, they also are used in other fields such as paper production, detergent, the textile industry, and in drinks and food technology in products manufacturing ranging from tea and coffee to fruit juice and wine. Recently, fungi have been used for the production of more than 50% of the needed enzymes. Fungi can produce different types of enzymes extracellularly, which gives a great chance for producing in large amounts with low cost and easy viability in purified forms using simple purification methods. In the present review, a comprehensive trial has been advanced to elaborate on the different types and structures of fungal enzymes as well as the current status of the uses of fungal enzymes in various applications.

Tyrosinase from Penicillium chrysogenum: Characterization and application in phenol removal from aqueous solution

The tyrosinase of Penicillium chrysogenum strain AUMC 14100 Accession No. MN219732 was purified to homogeneity and chemically modified by N-ethylmaleimide (NEM) and 5-(dimethylamino)naphthalene-1-sulfonyl chloride (dansyl chloride, DC). The inactivation of the purified enzyme obeyed pseudo-first-order reaction kinetics in the presence of NEM and DC (1-5 mM). The rate constants of the enzyme inactivation by NEM and DC were calculated to be 0.083 mol/min and 0.0013 mol/min, respectively. The recovery of enzyme activity by the protective effect of substrate indicates a non-specific modification of the active center. The order of tyrosinase inactivation kinetics and the substrate protection revealed the essentiality of sulfhydryl and lysyl residues in the enzyme active site and its role in the enzyme catalysis. The immobilized tyrosinase on alginate showed a gradual increase in residual activity over the immobilization time until the fourth hour. The desorptivity of tyrosinase was gradually raised with higher sodium dodecyl sulfate (SDS) concentrations. The immobilized enzyme retained about 70% of its original activity after 8 repeated cycles. Thus, immobilized tyrosinase of Penicillium chrysogenum removed 75% of phenol after 8 cycles and thus seems likely to be a good candidate for phenol removal in aqueous solution.