Protease production by thermo-alkaliphilic novel gut isolate Kitasatospora cheerisanensis GAP 12.4 from Gryllotalpa africana

Screening and Identification of Protease-Producing Microorganisms in the Gut of Gryllotalpa orientalis (Orthoptera: Gryllotalpidae)

The insect gut harbors a diverse array of functional microorganisms that warrant further exploration and utilization. However, there is currently a paucity of research reports on the discovery of protease-producing microorganisms with industrial application value in the gut. Here, we employed microbial culturing to screen and identify the protease-producing microorganisms in the gut extract of Gryllotalpa orientalis. Based on morphological, physiological, and biochemical characterization, 16S rRNA sequencing, as well as ANI and dDDH values of whole genome, the protease-producing strains isolated from the insect gut were identified as Priestia aryahattai DBM-1 and DX-4, P. megaterium DX-3, and Serratia surfactantfaciens DBM-5. According to whole-genome analysis, strain DBM-5, which exhibited the highest enzyme activity, possesses abundant membrane transport genes and carbohydrate metabolism enzymes. In contrast, strains DX-3 and DX-4 not only have the ability to hydrolyze proteins but also demonstrate the capability to hydrolyze plant materials. Furthermore, strains that are closely related tend to have similar metabolic product gene clusters in their genomes. The screening and identification of protease resources are essential for the subsequent development and utilization of gut functional microorganisms and genetic resources in insects.

Microorganism Contribution to Mass-Reared Edible Insects: Opportunities and Challenges

The interest in edible insects' mass rearing has grown considerably in recent years, thereby highlighting the challenges of domesticating new animal species. Insects are being considered for use in the management of organic by-products from the agro-industry, synthetic by-products from the plastics industry including particular detoxification processes. The processes depend on the insect's digestive system which is based on two components: an enzymatic intrinsic cargo to the insect species and another extrinsic cargo provided by the microbial community colonizing-associated with the insect host. Advances have been made in the identification of the origin of the digestive functions observed in the midgut. It is now evident that the community of microorganisms can adapt, improve, and extend the insect's ability to digest and detoxify its food. Nevertheless, edible insect species such as Hermetia illucens and Tenebrio molitor are surprisingly autonomous, and no obligatory symbiosis with a microorganism has yet been uncovered for digestion. Conversely, the intestinal microbiota of a given species can take on different forms, which are largely influenced by the host's environment and diet. This flexibility offers the potential for the development of novel associations between insects and microorganisms, which could result in the creation of synergies that would optimize or expand value chains for agro-industrial by-products, as well as for contaminants.

Microbes and microbial strategies in carcinogenic polycyclic aromatic hydrocarbons remediation: a systematic review

Degradation, detoxification, or removal of the omnipresent polycyclic aromatic hydrocarbons (PAHs) from the ecosphere as well as their prevention from entering into food chain has never appeared simple. In this context, cost-effective, eco-friendly, and sustainable solutions like microbe-mediated strategies have been adopted worldwide. With this connection, measures have been taken by multifarious modes of microbial remedial strategies, i.e., enzymatic degradation, biofilm and biosurfactant production, application of biochar-immobilized microbes, lactic acid bacteria, rhizospheric-phyllospheric-endophytic microorganisms, genetically engineered microorganisms, and bioelectrochemical techniques like microbial fuel cell. In this review, a nine-way directional approach which is based on the microbial resources reported over the last couple of decades has been described. Fungi were found to be the most dominant taxa among the CPAH-degrading microbial community constituting 52.2%, while bacteria, algae, and yeasts occupied 37.4%, 9.1%, and 1.3%, respectively. In addition to these, category-wise CPAH degrading efficiencies of each microbial taxon, consortium-based applications, CPAH degradation-related molecular tools, and factors affecting CPAH degradation are the other important aspects of this review in light of their appropriate selection and application in the PAH-contaminated environment for better human-health management in order to achieve a sustainable ecosystem.

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.

Unraveling the heavy metal resistance and biocontrol potential of Pseudomonas sp. K32 strain facilitating rice seedling growth under Cd stress

Heavy metal and metalloid toxicity in agricultural land needs special attention for crop production essential to feed increasing population globally. Plant growth-promoting rhizobacteria (PGPR) are native biological agents that have tremendous potential to augment crop production in contaminated fields. This study involves selection and identification (through 16S rRNA gene sequence and FAME analysis) of a potent Pseudomonas sp. (strain K32) isolated from a metal-contaminated rice rhizosphere, aimed to its application for sustainable agriculture. Apart from multi-heavy metal(loid) resistance (Cd²⁺, Pb²⁺ and As³⁺ upto 4000, 3800, 3700 μg/ml respectively) along with remarkable Cd bioaccumulation potential (∼90%), this strain showed IAA production, nitrogen-fixation and phosphate solubilization under Cd stress. This bioaccumulation efficiency coupled with PGP traits resulted in the significant enhancement of rice seedling growth under Cd stress. This positive impact of K32 strain was clearly manifested in morphological and biochemical improvements under Cd stress including successful root colonization with rice roots. Cd uptake was also reduced significantly in seedlings in presence of K32 strain. Together with all mentioned properties, K32 showed bio-control potential against plant pathogenic fungi viz. Aspergillus flavus, Aspergillus parasiticus, Paecilomyces sp., Cladosporium herbarum, Rhizopus stolonifer and Alternaria alternata which establish K32 strain a key player in effective bioremediation of agricultural fields. Biocontrol potential was found to be the result of enzymatic activities viz. chitinase, β-1,3-glucanase and protease which were estimated as 8.17 ± 0.44, 4.38 ± 0.35 and 7.72 ± 0.28 U/mg protein respectively.

Structural-genetic insight and optimization of protease production from a novel strain of Aeromonas veronii CMF, a gut isolate of Chrysomya megacephala

Structural-genetic characterization of protease producing genes and enzymes from microbial sources are seldom appreciated despite having its substantial utilization in protein engineering or genetic manipulation for biotechnological applications. Aeromonas veronii CMF, a mesophilic bacterium isolated from the gut of Chrysomya megacephala, was found to exhibited significant level of protease activity. For the revelation of genetic potential in relation to protease production, whole genome of this organism was sequenced and analysed while structure-function of different protease enzyme was predicated using various in silico analysis. The 4.5 mb CMF genome was found to encompass various types of protease and mostly they are neutral in nature. Enzyme production was highest in an optimum pH and temperature of 6.0 (32.09 ± 1.015 U/ml) and 35ºC (41.65 ± 1.152 U/ml), respectively. Other culture parameters for optimum production of protease were determined to be inoculum size (1%), incubation period (72 h), shaking condition (125 rpm), carbon and nitrogen source [2% lactose (92.21 ± 3.16 U/ml) and 0.5% urea (163.62 ± 4.31 U/ml), respectively] and effect of surfactants [0.02 mg/ml Tween 80 (174.72 ± 4.48 U/ml)]. Furthermore, A. veronii CMF exhibited significant enzyme production like serine protease (15.22 ± 0.563 U/ml), aspartate protease (33.16 ± 0.762 U/ml) and collagenase (17.26 ± 0.626 U/ml). Genomic information and results of physio-biochemical assays indicate its cost-effective potential use in different enzyme-industry.