Wealth from waste: Optimized alkaline protease production from agro-industrial residues by Bacillus alcalophilus LW8 and its biotechnological applications

Application of the novel manta-ray foraging algorithm to optimize acidic peptidase production in solid-state fermentation using binary agro-industrial waste

Peptidases, which constitute about 20% of the global enzyme market, have found applications in detergent, food and pharmaceutical industries, and could be produced on a large scale using low-cost agro-industrial waste. An acidophilic Bacillus cereus strain produced acidic peptidase on binary-agro-industrial waste comprising yam peels and fish processing waste at pH 4.5 with high catalytic activity. A five-variable central composite rotatable design of a response surface methodology was used to model bioprocess conditions for improved peptidase production in solid-state fermentation. Data generated was leveraged as the basis for applying the novel Manta-ray foraging optimization-linked feed-forward artificial neural network to predict bioprocess conditions optimally. Results obtained from the optimization experiments revealed a significant coefficient of determination of 0.9885 with low-performance error. The bioprocess predicted a peptidase activity of 1035.32 U/mL under optimized conditions set as 54.8 g/100 g yam peels, 23.85 g/100 g fish waste, 0.31 g/100 g CaCl2, 47.54% (v/w) moisture content, and pH 2. Peptidase activity was improved 5-fold, and was stable for 240 min between pH 2.5 and 3.5. Michaelis-Menten kinetics revealed a Km of 0.119 mM and a catalytic efficiency of 45462.19 mM-1 min-1. The bioprocess holds promise for sustainable enzyme-driven applications.

Microbial proteases and their applications

Proteases (proteinases or peptidases) are a class of hydrolases that cleave peptide chains in proteins. Endopeptidases are a type of protease that hydrolyze the internal peptide bonds of proteins, forming shorter peptides; exopeptidases hydrolyze the terminal peptide bonds from the C-terminal or N-terminal, forming free amino acids. Microbial proteases are a popular instrument in many industrial applications. In this review, the classification, detection, identification, and sources of microbial proteases are systematically introduced, as well as their applications in food, detergents, waste treatment, and biotechnology processes in the industry fields. In addition, recent studies on techniques used to express heterologous microbial proteases are summarized to describe the process of studying proteases. Finally, future developmental trends for microbial proteases are discussed.

A novel strain of Stenotrophomonas acidaminiphila produces thermostable alkaline peptidase on agro-industrial wastes: process optimization, kinetic modeling and scale-up

Bacterial alkaline peptidases, especially from Bacillus species, occupy the frontline in global enzyme market, albeit with poor production economics. Here, we report the deployment of response surface methodology approximations to optimize fermentation parameters for enhanced yield of alkaline peptidase by the non-Bacillus bacterium; Stenotrophomonas acidaminiphila. Shake flask production under optimized conditions was scaled up in a 5-L bench-scale bioreactor. Logistic and modified Gompertz models revealed significant fits for biomass formation, total protein, and substrate consumption models. Maximum specific growth rate (µ_max = 0.362 h^-1) of the bacterium in the optimized medium did not differ significantly from those in Luria-Bertani and trypticase soy broths. The aqueous two-phase system-purified 45.7 kDa alkaline protease retained 83% activity which improved with increasing sodium dodecyl sulfate concentration thus highlighting potential laundry application. Maximum enzyme activity occurred at 75ºC and pH 10.5 but was inhibited by 5 mM phenyl-methyl-sulfonyl fluoride suggesting a serine-protease nature.

Understanding the Basis of Occurrence, Biosynthesis, and Implications of Thermostable Alkaline Proteases

The group of hydrolytic enzymes synonymously known as proteases is predominantly most favored for the class of industrial enzymes. The present work focuses on the thermostable nature of these proteolytic enzymes that occur naturally among mesophilic and thermophilic microbes. The broad thermo-active feature (40-80 °C), ease of cultivation, maintenance, and bulk production are the key features associated with these enzymes. Detailing of contemporary production technologies, and controllable operational parameters including the purification strategies, are the key features that justify their industrial dominance as biocatalysts. In addition, the rigorous research inputs by protein engineering and enzyme immobilization studies add up to the thermo-catalytic features and application capabilities of these enzymes. The work summarizes key features of microbial proteases that make them numero-uno for laundry, biomaterials, waste management, food and feed, tannery, and medical as well as pharmaceutical industries. The quest for novel and/or designed and engineered thermostable protease from unexplored sources is highly stimulating and will address the ever-increasing industrial demands.

Two steps purification, biochemical characterization, thermodynamics and structure elucidation of thermostable alkaline serine protease from Nocardiopsis alba strain OM-5

The Nocardiopsis alba strain OM-5 showed maximum protease production in submerged culture. The OM-5 protease was purified by hydrophobic interaction chromatography. The purified protease of 68 kDa showed maximum activity (3312 ± 1.64 U/mL) at 70 °C and was quite stable at 80 °C up to 4 M NaCl (w/v) at pH 9. The purified protease showed significant activity and stability in different cations, denaturing agents, metal ions, and osmolytes. The thermodynamic parameters including deactivation rate constant (K_d) and half lives (t_1/2) at 50-80 °C were in the range of 2.50 × 10^-3 to 5.50 × 10^-3 and 277.25-111.25 min respectively at 0-4 M NaCl. The structural stability of the OM-5 protease under various harsh conditions was elucidated by circular dichroism (CD) spectroscopy followed by K2D3 analysis revealed that the native structure of OM-5 protease was stable even in sodium dodecyl sulfate and Tween 20 indicated by increased α-helices content assisted with decreased β-sheets content.

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.

Statistical optimisation of protease production using a freshwater bacterium Chryseobacterium cucumeris SARJS-2 for multiple industrial applications

Feathers, rich in keratin, are usually the unused by-products of poultry industries. In addition, the cast-off X-ray films serve as secondary sources of silver, and the traditional method of silver extraction from this source is costly and not eco-friendly. Therefore, the current study focuses on protease production using a freshwater bacterium Chryseobacterium cucumeris SARJS-2, aiming to convert these wastes into useful products. The protease production was optimized by one-factor-at-a-time (OFAT), followed by Plackett Burman design (PBD) and response surface methodology (RSM). The protease production got enhanced by more than two folds after the statistical optimisation. Upon partial purification, the enzyme activity increased by approximately three folds. The protease was active in the range of temperatures from 25 to 75 °C, but the optimum temperature was recorded as 35 °C. The protease exhibited detergent compatibility and organic solvent stability. The detergent compatibility suggests the protease could be a detergent additive. It was also found that the presence of Fe⁺² enhanced protease activity. The protease was tested for stain removal, feather degradation and silver recovery applications. It was found that the protease could efficiently remove stains of blood and tomato sauce. In addition, the protease was found to be a successful candidate for feather degradation, thereby feather-hydrolysate production which has prominent roles as nature-friendly fertilizer and animal feed ingredient. The protease also degraded gelatin from the X-ray films to release the silver-halides for silver recovery. The results recommend that the SARJS-2 protease is a potential candidate for use in eco-friendly applications in various industrial sectors.

Optimization of Protease and Amylase Production by Rhizopus oryzae Cultivated on Bread Waste Using Solid-State Fermentation

This research was carried for the coproduction of two industrial enzymes: α-amylase and protease via SSF by Rhizopus oryzae on humidified bread waste. Fermentation time, inoculum size, initial moisture content, salt solutions, and the thickness of the substrate were investigated one by one. Fungus culture was carried out in sterile aluminum trays, and pH was adjusted to 5.5. The main results showed that the highest levels of enzyme production were obtained at 120 h, 65% relative humidity, height media of 1 cm, 105 spore/g, and M-9 solution (g/L): NaH2PO4, 12.8; KH2PO4, 3; NaCl, 0.5; NH4Cl, 1; MgSO4 7H2O, 0.5; CaCl2 2H2O, 0.01. α-Amylase (100 U/g) and protease (2400 U/g) produced by SSF from Rhizopus oryzae (CH4) on BW as substrate are of great interest in industries and could be valorized as enhancers of the bread making process.

Use of statistical experimental methods for optimization of collagenolytic protease production by Bacillus cereus strain SUK grown on fish scales

In this study, novel and cheap sources like fish scales and molasses were used for the production of collagenolytic protease. Statistical optimization of different parameters for the production of collagenolytic protease by Bacillus cereus strain SUK has been carried out using response surface methodology (RSM). Three most significant medium components identified by Plackett-Burman (PB) were fish scales, molasses, and incubation time, which were further optimized using central composite design (CCD). The medium having fish scales 9.38 g l^-1, molasses 2.42 g l^-1, and incubation time of 67.34 h was found to be optimum for maximum collagenolytic protease production. B. cereus strain SUK has shown multiple plant growth-promoting traits, whereas degraded fish scale hydrolysates (FSHs) were having antimicrobial as well as plant growth-promoting abilities. The collagenolytic efficiency of this isolate can be exploited in an eco-friendly process of bioconversion of fish waste, representing an alternative way of waste management that could be used to produce various value-added products, such as collagenolytic protease, microbial biomass, amino acids, protein hydrolysates, and collagen peptides.

Fish Waste-Potential Low Cost Substrate for Bacterial Protease Production: A Brief Review

Industrial biotechnology processes have recently been exploited for an economic utilization of wastes to produce value added products. Of which, fish waste is one of the rich sources of proteins that can be utilized as low cost substrates for microbial enzyme production. Fish heads, tails, fins, viscera and the chitinous materials make up the wastes from fish industries. Processing these wastes for the production of commercial value added products could result in a decrease in the cost of production. In addition, we can eliminate the pollution of the environment and health issues due to the improper disposal of these fish wastes. This review highlights the potential use of fish waste as a cheaper substrate for the production of economically important protease enzyme.

Data on optimized production and characterization of alkaline proteases from newly isolated alkaliphiles from Lonar soda lake, India

Alkaline proteases are one of the industrially important enzymes and generally preferred from alkaliphilic sources. Here we have provided the data on optimized production and characterization of alkaline proteases from five newly isolated and identified alkaliphiles from Lonar soda lake, India. The data provided for optimization of physicochemical parameters for maximum alkaline proteases production is based on OVAT (one variable at a time) approach. Alkaline protease production (U/mL) recorded by using different agro industrial residues is included in the given data. Further readers can find more information in our previously published research article where we have already described about the methods used and comparative analysis of the data recorded regarding optimized production, characterization and application of alkaline proteases isolated from Lonar soda lake isolates (http://dx.doi.org/10.1016/j.bcab.2016.06.002) [1]. The data provided here by us is useful to other researchers for setting up various suitable statistical models to perform optimization studies other than OVAT approach.