Isolation and Characterization of a Protease Producing Bacteria Bacillus amovivorus and Optimization of Some Factors of Culture Conditions for Protease Production

Unleashing the Potential of Bacterial Isolates from Apple Tree Rhizosphere for Biocontrol of Monilinia laxa: A Promising Approach for Combatting Brown Rot Disease

Monilinia laxa, a notorious fungal pathogen responsible for the devastating brown rot disease afflicting apples, wreaks havoc in both orchards and storage facilities, precipitating substantial economic losses. Currently, chemical methods represent the primary means of controlling this pathogen in warehouses. However, this study sought to explore an alternative approach by harnessing the biocontrol potential of bacterial isolates against brown rot in apple trees. A total of 72 bacterial isolates were successfully obtained from the apple tree rhizosphere and subjected to initial screening via co-cultivation with the pathogen. Notably, eight bacterial isolates demonstrated remarkable efficacy, reducing the mycelial growth of the pathogen from 68.75 to 9.25%. These isolates were subsequently characterized based on phenotypic traits, biochemical properties, and 16S rRNA gene amplification. Furthermore, we investigated these isolates' production capacity with respect to two enzymes, namely, protease and chitinase, and evaluated their efficacy in disease control. Through phenotypic, biochemical, and 16S rRNA gene-sequencing analyses, the bacterial isolates were identified as Serratia marcescens, Bacillus cereus, Bacillus sp., Staphylococcus succinus, and Pseudomonas baetica. In dual culture assays incorporating M. laxa, S. marcescens and S. succinus exhibited the most potent degree of mycelial growth inhibition, achieving 68.75 and 9.25% reductions, respectively. All the bacterial isolates displayed significant chitinase and protease activities. Quantitative assessment of chitinase activity revealed the highest levels in strains AP5 and AP13, with values of 1.47 and 1.36 U/mL, respectively. Similarly, AP13 and AP6 exhibited the highest protease activity, with maximal enzyme production levels reaching 1.3 and 1.2 U/mL, respectively. In apple disease control assays, S. marcescens and S. succinus strains exhibited disease severity values of 12.34% and 61.66% (DS), respectively, highlighting their contrasting efficacy in mitigating disease infecting apple fruits. These findings underscore the immense potential of the selected bacterial strains with regard to serving as biocontrol agents for combatting brown rot disease in apple trees, thus paving the way for sustainable and eco-friendly alternatives to chemical interventions.

Production of subtilisin proteases in bacteria and yeast

In this review, we discuss the progress in the study and modification of subtilisin proteases. Despite longstanding applications of microbial proteases and a large number of research papers, the search for new protease genes, the construction of producer strains, and the development of methods for their practical application are still relevant and important, judging by the number of citations of the research articles on proteases and their microbial producers. This enzyme class represents the largest share of the industrial production of proteins worldwide. This situation can explain the high level of interest in these enzymes and points to the high importance of designing domestic technologies for their manufacture. The review covers subtilisin classification, the history of their discovery, and subsequent research on the optimization of their properties. An overview of the classes of subtilisin proteases and related enzymes is provided too. There is a discussion about the problems with the search for (and selection of) subtilases from natural strains of various microorganisms, approaches to (and specifics of) their modification, as well as the relevant genetic engineering techniques. Details are provided on the methods for expression optimization of industrial subtilases of various strains: the details of the most important parameters of cultivation, i.e., composition of the media, culture duration, and the influence of temperature and pH. Also presented are the results of the latest studies on cultivation techniques: submerged and solid-state fermentation. From the literature data reviewed, we can conclude that native enzymes (i.e., those obtained from natural sources) currently hardly have any practical applications because of the decisive advantages of the enzymes modified by genetic engineering and having better properties: e.g., thermal stability, general resistance to detergents and specific resistance to various oxidants, high activity in various temperature ranges, independence from metal ions, and stability in the absence of calcium. The vast majority of subtilisin proteases are expressed in producer strains belonging to different species of the genus Bacillus. Meanwhile, there is an effort to adapt the expression of these enzymes to other microbes, in particular species of the yeast Pichia pastoris.

Isolation, screening, characterization, and identification of alkaline protease-producing bacteria from leather industry effluent

Background

A wide variety of bacterial species produces protease enzyme, and the application of the same enzyme has been manipulated precisely and used in various biotechnological areas including industrial and environmental sectors. The main aim of this research study was to isolate, screen, and identify alkaline protease-producing bacteria that were sampled from leather industry effluent present in the outer skirts of Addis Ababa, Ethiopia.

Purpose

To isolate and characterize the alkaline protease-producing bacteria from leather industrial effluents.

Methods

Samples are collected from Modji leather industrial effluents and stored in the microbiology lab. After isolated bacteria from effluent using serial dilution and followed by isolated protease-producing bacteria using skim milk agar media. After studying primary and secondary screening using zonal inhibition methods to select potential protease-producing bacteria using skim milk agar media. Finally, to identify the potential bacteria using biochemical methods, bacterial biomass, protease activity, and gene sequencing (16S rRNA) method to finalize the best alkaline protease producing bacteria identified.

Results

First twenty-eight different bacterial colonies were isolated initially from the leather industry effluent sample situated at the Modjo town of Ethiopia. The isolated bacteria were screened using the primary and secondary screening method with skim milk agar medium. At the primary level, we selected three isolates namely ML5(14 mm), ML12(18 mm), and MS12 (15 mm), showing the highest zone of proteolysis as a result of casein degradation on the agar plates were selected and subjected to primary screening. Further secondary screening confirmed that the zone of inhibition methods ML5 (14.00±0.75 mm), ML12 (19.50±0.66 mm), and MS12 (15.00±1.32 mm) has efficient proteolytic activity and can be considered as effective protease producer. The three isolates were then subjected to morphological and biochemical tests to identify probably bacterial species, and all the three bacterial isolates were found out to be of Bacillus species. The shake flask method was carried out to identify the most potent one having greater biomass production capabilities and protease activity. ML12 isolated from leather effluent waste showed the highest protease activity (19 U/ml), high biomass production, and the same was subjected to molecular identification using 16s sequencing and a phylogenetic tree was constructed to identify the closest neighbor. The isolate ML12 (Bacillus cereus strain -MN629232.1) is 97.87% homologous to Bacillus cereus strain (KY995152.1) and 97.86% homologous to Bacillus cereus strain (MK968813.1).

Conclusions

This study has exposed that from twenty-eight different bacterial samples isolated from leather industry effluent; further primary and secondary screening methods were selected three potential alkaline protease strains. Finally, based on its biochemical identification, biomass, and protease activity, ML12 (Bacillus cereus strains) is the best strain identified. The alkaline protease has the significant feature of housing potent bacterial species for producing protease of commercial value.

Microbial alkaline proteases: Optimization of production parameters and their properties

Proteases are hydrolytic enzymes capable of degrading proteins into small peptides and amino acids. They account for nearly 60% of the total industrial enzyme market. Proteases are extensively exploited commercially, in food, pharmaceutical, leather and detergent industry. Given their potential use, there has been renewed interest in the discovery of proteases with novel properties and a constant thrust to optimize the enzyme production. This review summarizes a fraction of the enormous reports available on various aspects of alkaline proteases. Diverse sources for isolation of alkaline protease producing microorganisms are reported. The various nutritional and environmental parameters affecting the production of alkaline proteases in submerged and solid state fermentation are described. The enzymatic and physicochemical properties of alkaline proteases from several microorganisms are discussed which can help to identify enzymes with high activity and stability over extreme pH and temperature, so that they can be developed for industrial applications.

Characterizing novel thermophilic amylase producing bacteria from taptapani hot spring, odisha, India

BACKGROUND

Amylases play a vital role in biotechnological studies and rank an important position in the world enzyme market (25% to 33%). Bioprocess method of amylase production is more effective than the other sources, since the technique is easy, cost effective, fast, and the enzymes of required properties can be procured.

OBJECTIVES

The current study aimed to report the characteristics of novel amylase producing bacterial strains isolated from Taptapani hot spring, Odisha, India.

MATERIALS AND METHODS

Bacterial strains were isolated by dilution plating method from the water samples collected from Taptapani Hot Spring, Odisha and screened for amylase production through starch hydrolysis. The bacterial isolates were identified morphologically, biochemically, and finally by 16S rDNA profiling.

RESULTS

Based on the morphological, physiological, biochemical characteristics and the molecular characterization, the isolates SS1, SS2, and SS3 were identified as Bacillus barbaricus, Aeromonas veroni, and Stenotrophomonas maltophilia, respectively. The approximate molecular weight of enzymes from SS1, SS2, and SS3 strains were 19 kDa, 56 kDa and 49 kDa, respectively.

CONCLUSIONS

The current report isolates, characterizes, and demonstrates the novel heat-adapted amylase-producing bacteria SS1, SS2 and SS3 from Taptapani hot spring, indicating its potentiality and stability under acidic conditions.

Bacillus subtillis RTSBA6 6.00, a new strain isolated from gut of Helicoverpa armigera (Lepidoptera: Noctuidae) produces chymotrypsin-like proteases

Exploring bacterial communities with proteolytic activity from the gut of the Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) insect pests was the purpose of this study. As initial efforts to achieve this goal here we report the isolation of new Bacillus subtillis RTSBA6 6.00 strain from the gut of H. armigera and demonstrated as proteases producer. Zymographic analysis revealed 12 proteolytic bands with apparent molecular weights ranging from 20 to 185 kDa. Although some activity was detected at acidic pH, the major activity was observed at slight alkaline pH (7.8). The optimum temperature was found to be 35 °C with complete loss of activity at 70 °C. All proteases were completely inactivated by PMSF (phenylmethylsulfonyl fluoride) and TPCK (N-tosyl-l-phenylalanine chloromethyl ketone), suggesting that proteases secreted by B. subtillis RTSBA6 6.00 belong to serine proteases class with chymotrypsin-like activity. The occurrence of protease producing bacterial community in the gut of the H. armigera advocates its probable assistance to insect in proteinaceous food digestion and adaptation to protease inhibitors of host plants.

l-Asparaginase Production by Moderate Halophilic Bacteria Isolated from Maharloo Salt Lake

l-Asparaginase is an anti-neoplastic drug used in lymphoblastic leukemia chemotherapy. Nowadays, this enzyme derived from bacterial sources, mostly l-asparaginase II from Escherichia coli and in lesser amount l-asparaginase of Erwinia sp. has medical utilization. The long-term usage of these agents leads to allergic reactions and new asparaginase with new immunological characteristics is required. Halophilic bacteria might contain l-asparaginase with novel immunological properties that can be used in hypersensitive patients. In this experiment, we have screened moderate Halophilic bacteria for l-asparaginase production ability and showed that Halophilic bacteria produce intra- and extracellular l-asparaginase. Bacillus sp. BCCS 034 was found to produce the highest l-asparaginase (1.64 IU/ml supernatant) extracellularly.