Potential Biotechnological Applications Research Articles

Identification and characterization of methoxy- and dimethoxyhydroquinone 1,2-dioxygenase from Phanerochaete chrysosporium.

White-rot fungi, such as Phanerochaete chrysosporium, are the most efficient degraders of lignin, a major component of plant biomass. Enzymes produced by these fungi, such as lignin peroxidases and manganese peroxidases, break down lignin polymers into various aromatic compounds based on guaiacyl, syringyl, and hydroxyphenyl units. These intermediates are further degraded, and the aromatic ring is cleaved by 1,2,4-trihydroxybenzene dioxygenases. This study aimed to characterize homogentisate dioxygenase (HGD)-like proteins from P. chrysosporium that are strongly induced by the G-unit fragment of vanillin. We overexpressed two homologous recombinant HGDs, PcHGD1 and PcHGD2, in Escherichia coli. Both PcHGD1 and PcHGD2 catalyzed the ring cleavage in methoxyhydroquinone (MHQ) and dimethoxyhydroquinone (DMHQ). The two enzymes had the highest catalytic efficiency (kcat/Km) for MHQ, and therefore, we named PcHGD1 and PcHGD2 as MHQ dioxygenases 1 and 2 (PcMHQD1 and PcMHQD2), respectively, from P. chrysosporium. This is the first study to identify and characterize MHQ and DMHQ dioxygenase activities in members of the HGD superfamily. These findings highlight the unique and broad substrate spectra of PcHGDs, rendering them attractive candidates for biotechnological applications.IMPORTANCEThis study aimed to elucidate the properties of enzymes responsible for degrading lignin, a dominant natural polymer in terrestrial lignocellulosic biomass. We focused on two homogentisate dioxygenase (HGD) homologs from the white-rot fungus, P. chrysosporium, and investigated their roles in the degradation of lignin-derived aromatic compounds. In the P. chrysosporium genome database, PcMHQD1 and PcMHQD2 were annotated as HGDs that could cleave the aromatic rings of methoxyhydroquinone (MHQ) and dimethoxyhydroquinone (DMHQ) with a preference for MHQ. These findings suggest that MHQD1 and/or MHQD2 play important roles in the degradation of lignin-derived aromatic compounds by P. chrysosporium. The preference of PcMHQDs for MHQ and DMHQ not only highlights their potential for biotechnological applications but also underscores their critical role in understanding lignin degradation by a representative of white-rot fungus, P. chrysosporium.

Investigation of Magneto Hydrodynamics Properties of Reiner–Philippoff Nanofluid with Gyrotactic Microorganism in a Porous Medium

Investigation of Magneto Hydrodynamics Properties of Reiner–Philippoff Nanofluid with Gyrotactic Microorganism in a Porous Medium Nanofluids have many potential applications in engineering, medicine, and biotechnology due to their enhanced thermal, electrical, and optical properties. However, the flow and heat transfer characteristics of nanofluids are influenced by various factors, such as the type and size of nanoparticles, the base fluid, the magnetic field, the radiation, the chemical reaction, and the presence of microorganisms. Therefore, it is important to study the effects of these factors on the nanofluid flow and heat transfer using mathematical models and numerical methods. One of the mathematical models that can describe the nanofluid flow is the Reiner-Philippoff model, which is a classical non-Newtonian fluid model that accounts for the shear-thinning behaviour of some fluids. The Reiner-Philippoff model has been used to study the nanofluid flow over a stretching sheet, which is a simplified model of many industrial processes involving stretching or shrinking surfaces. However, most of the previous studies have neglected the effects of the Arrhenius reaction, thermal radiation, viscous dissipation, and bio-convection on the nanofluid flow over a stretching sheet. The objective of this paper is to fill this gap by conducting a numerical investigation of the effects of the Arrhenius reaction, thermal radiation, viscous dissipation, and bio-convection on a Reiner-Philippoff nanofluid of MHD flow through a stretching sheet. This also considers the effects of thermophoresis and Brownian motion, which are two mechanisms that govern the transport of nanoparticles in nanofluids. The article utilized a similarity transformation to reduce the governing partial differential equations into ordinary differential equations, which are then solved by using the MATLAB computational tool bvp4c technique. The paper also employs a hybrid numerical solution method using Runge-Kutta fourth order with a shooting technique and an optimization technique using the Bayesian regularization method for Runge-Kutta to improve the accuracy of the prediction outcomes. The main finding of this paper is that the Arrhenius reaction, thermal radiation, viscous dissipation, and bio-convection have significant effects on the velocity, temperature, concentration, and motile microorganism profiles of the nanofluid flow over a stretching sheet. The paper also discusses how these effects can be controlled by varying the relevant parameters. This provides graphical results for the profiles of velocity, temperature, concentration, and motile microorganisms for different values of these parameters. The study also compares its results with some existing results in the literature and finds good agreement.

Additive Manufacturing Applications in Biosensors Technologies.

Three-dimensional (3D) printing technology, also known as additive manufacturing (AM), has emerged as an attractive state-of-the-art tool for precisely fabricating functional materials with complex geometries, championing several advancements in tissue engineering, regenerative medicine, and therapeutics. However, this technology has an untapped potential for biotechnological applications, such as sensor and biosensor development. By exploring these avenues, the scope of 3D printing technology can be expanded and pave the way for groundbreaking innovations in the biotechnology field. Indeed, new printing materials and printers would offer new possibilities for seamlessly incorporating biological functionalities within the growing 3D scaffolds. Herein, we review the additive manufacturing applications in biosensor technologies with a particular emphasis on extrusion-based 3D printing modalities. We highlight the application of natural, synthetic, and composite biomaterials as 3D-printed soft hydrogels. Emphasis is placed on the approach by which the sensing molecules are introduced during the fabrication process. Finally, future perspectives are provided.

Cannabis Roots: Therapeutic, Biotechnological and Environmental Aspects.

Since the legalization of recreational cannabis in Canada in 2018, the number of licenses for this crop has increased significantly, resulting in an increase in waste generated. Nevertheless, cannabis roots were once used for their therapeutic properties, indicating that they could be valued today rather than dismissed. This review will focus on both traditional therapeutic aspects and potential use of roots in modern medicine while detailing the main studies on active phytomolecules found in cannabis roots. The environmental impact of cannabis cultivation and current knowledge of the root-associated microbiome are also presented as well as their potential applications in biotechnology and phytoremediation. Thus, several high added-value applications of cannabis roots resulting from scientific advances in recent years can be considered to remove them from discarded residues.

Proteomic analysis of the mucus of the photosynthetic sea slug Elysia crispata

Elysia crispata is a tropical sea slug that can retain intracellular functional chloroplasts from its algae prey, a mechanism termed kleptoplasty. This sea slug, like other gastropods, secretes mucus, a viscous secretion with multiple functions, including lubrication, protection, and locomotion. This study presents the first comprehensive analysis of the mucus proteome of the sea slug E. crispata using gel electrophoresis and HPLC-MS/MS. We identified 306 proteins in the mucus secretions of this animal, despite the limited entries for E. crispata in the Uniprot database. The functional annotation of the mucus proteome using Gene Ontology identified proteins involved in different functions such as hydrolase activity (molecular function), carbohydrate-derived metabolic processes (biological processes) and cytoskeletal organization (cell component). Moreover, a high proportion of proteins with enzymatic activity in the mucus of E. crispata suggests potential biotechnological applications including antimicrobial and antitumor activities. Putative antimicrobial properties are reinforced by the high abundance of hydrolases. This study also identified proteins common in mucus samples from various species, supporting a common mechanism of mucus in protecting cells and tissues while facilitating animal movement. SignificanceMarine species are increasingly drawing the interest of researchers for their role in discovering new bioactive compounds. The study “Proteomic Analysis of the Mucus of the Photosynthetic Sea Slug Elysia crispata” is a pioneering effort that uncovers the complex protein content in this fascinating sea slug's mucus.This detailed proteomic study has revealed proteins with potential use in biotechnology, particularly for antimicrobial and antitumor purposes. This research is a first step in exploring the possibilities within the mucus of Elysia crispata, suggesting the potential for new drug discoveries. These findings could be crucial in developing treatments for severe diseases, especially those caused by multidrug-resistant bacteria, and may lead to significant advances in medical research.

Compiling a versatile toolbox for inducible gene expression in Methanosarcina mazei

Abstract Methanosarcina mazei is a model organism, providing a platform to explore methanoarchaeal regulation mechanisms on the transcriptional and translational level. This study investigates and evaluates various molecular tools to allow inducible gene expression in M. mazei. (i) The TetR/TetO system was utilized to induce expression of a designed antisense RNA directed against sRNA154 allowing to increase transcripts of asRNA154 (500-fold), resulting in a significant decrease of sRNA154 levels (tetracycline-induced knockdown mutant). Strong reduction of sRNA154 was further confirmed in the knockdown mutant by up to 50-fold decreased transcript levels of the genes nifH, glnK1, and glnA1, the stability of which is increased by sRNA154. (ii) For translational regulation, an RNA thermometer was designed and first-ever utilized in an archaeon, inserted into the 5′-untranslated region of a reporter gene, which showed enhanced protein expression upon a temperature shift from 30°C to 40°C. (iii) The long 5′-UTR of a trimethylamine (TMA)-inducible polycistronic mRNA was evaluated and studied as a potential genetic tool for induced gene expression on the translational level. However, we discovered TMA-dependent regulation occurs most likely on the transcript level. (iv) A new selection marker (nourseothricin resistance) was established for M. mazei using the streptothricin acetyltransferase gene. Taken together, our findings provide a foundation for future exploration of genetic regulation and inducible gene expression in M. mazei and other methanoarchaea, advancing genetic studies in these organisms and enhancing their potential for biotechnology applications.

Unveiling nature's treasures: actinobacteria from Meghalaya's mining sites as sources of bioactive compounds.

Coal and sillimanite mining sites present unique ecological niches favoring the growth of actinobacteria, a group of Gram-positive bacteria known for producing a wide array of bioactive compounds. Isolating these bacteria from such environments could unveil novel compounds with potential biotechnological applications. This study involved the isolation of actinobacteria from two mining sites in Meghalaya, India. The dominant genera from both sites were Streptomyces, Amycolatopsis, Nocardia, and Streptosporangium. Metabolic pathway prediction from 16S rRNA gene revealed several pathways beneficial for plant growth. Exploration of biosynthetic genes indicated a prevalence of the type-II polyketide synthase gene. Sequencing the ketosynthase-alpha domain of the gene led to predictions of various bioactive secondary metabolites. Around 44% of the isolates demonstrated antimicrobial properties, with some also displaying plant growth-promoting traits. Amycolatopsis SD-15 exhibited promising results in planta when tested on tomato plants. These findings highlight the potential of actinobacteria from Meghalaya's mining sites across medical, agricultural, and industrial domains.

DNA transfer between two different species mediated by heterologous cell fusion in Clostridium coculture.

Prokaryotic evolution is driven by random mutations and horizontal gene transfer (HGT). HGT occurs via transformation, transduction, or conjugation. We have previously shown that in syntrophic cocultures of Clostridium acetobutylicum and Clostridium ljungdahlii, heterologous cell fusion leads to a large-scale exchange of proteins and RNA between the two organisms. Here, we present evidence that heterologous cell fusion facilitates the exchange of DNA between the two organisms. Using selective subculturing, we isolated C. acetobutylicum cells which acquired and integrated into their genome portions of plasmid DNA from a plasmid-carrying C. ljungdahlii strain. Limiting-dilution plating and DNA methylation data based on PacBio Single-Molecule Real Time (SMRT) sequencing support the existence of hybrid C. acetobutylicum/C. ljungdahlii cells. These findings expand our understanding of multi-species microbiomes, their survival strategies, and evolution.IMPORTANCEInvestigations of natural multispecies microbiomes and synthetic microbial cocultures are attracting renewed interest for their potential application in biotechnology, ecology, and medical fields. Previously, we have shown the syntrophic coculture of C. acetobutylicum and C. ljungdahlii undergoes heterologous cell-to-cell fusion, which facilitates the exchange of cytoplasmic protein and RNA between the two organisms. We now show that heterologous cell fusion between the two Clostridium organisms can facilitate the exchange of DNA. By applying selective pressures to this coculture system, we isolated clones of wild-type C. acetobutylicum which acquired the erythromycin resistance (erm) gene from the C. ljungdahlii strain carrying a plasmid with the erm gene. Single-molecule real-time sequencing revealed that the erm gene was integrated into the genome in a mosaic fashion. Our data also support the persistence of hybrid C. acetobutylicum/C. ljungdahlii cells displaying hybrid DNA-methylation patterns.

Comparison of two peroxidases with high potential for biotechnology applications – HRP vs. APEX2

Peroxidases are essential elements in many biotechnological applications. An especially interesting concept involves split enzymes, where the enzyme is separated into two smaller and inactive proteins that can dimerize into a fully active enzyme. Such split forms were developed for the horseradish peroxidase (HRP) and ascorbate peroxidase (APX) already. Both peroxidases have a high potential for biotechnology applications. In the present study, we performed biophysical comparisons of these two peroxidases and their split analogues. The active site availability is similar for all four structures. The split enzymes are comparable in stability with their native analogues, meaning that they can be used for further biotechnology applications. Also, the tertiary structures of the two peroxidases are similar. However, differences that might help in choosing one system over another for biotechnology applications were noticed. The main difference between the two systems is glycosylation which is not present in the case of APX/sAPEX2, while it has a high impact on the HRP/sHRP stability. Further differences are calcium ions and cysteine bridges that are present only in the case of HRP/sHRP. Finally, computational results identified sAPEX2 as the systems with the smallest structural variations during molecular dynamics simulations showing its dominant stability comparing to other simulated proteins. Taken all together, the sAPEX2 system has a high potential for biotechnological applications due to the lack of glycans and cysteines, as well as due to high stability.

Mining the microbiome of Lake Afdera to gain insights into microbial diversity and biosynthetic potential.

Microorganisms inhabiting hypersaline environments have received significant attention due to their ability to thrive under poly-extreme conditions, including high salinity, elevated temperatures and heavy metal stress. They are believed to possess biosynthetic gene clusters (BGCs) that encode secondary metabolites as survival strategy and offer potential biotechnological applications. In this study, we mined BGCs in shotgun metagenomic sequences generated from Lake Afdera, a hypersaline lake in the Afar Depression, Ethiopia. The microbiome of Lake Afdera is predominantly bacterial, with Acinetobacter (18.6%) and Pseudomonas (11.8%) being ubiquitously detected. A total of 94 distinct BGCs were identified in the metagenomic data. These BGCs are found to encode secondary metabolites with two main categories of functions: (i) potential pharmaceutical applications (nonribosomal peptide synthase NRPs, polyketide synthase, others) and (ii) miscellaneous roles conferring adaptation to extreme environment (bacteriocins, ectoine, others). Notably, NRPs (20.6%) and bacteriocins (10.6%) were the most abundant. Furthermore, our metagenomic analysis predicted gene clusters that enable microbes to defend against a wide range of toxic metals, oxidative stress and osmotic stress. These findings suggest that Lake Afdera is a rich biological reservoir, with the predicted BGCs playing critical role in the survival and adaptation of extremophiles.

Entropy optimization of chemically reactive bioconvective Powell-Eyring nanofluid stratified flow over a Riga plate: A non-Fourier heat and mass flux modeling

This work examines the effects of Riga plate flow in a Powell-Eyring bioconvection Powell-Forchheimer medium. For the Powell-Eyring base fluid, mobile microorganisms are taken into account in addition to nanoparticles. Additionally taken into account are chemical reactions and the effects of linear radiation. The governing PDEs with boundary conditions are transformed into an ODE by using similarity transformation. The resulting equations are solved using the homotopy analysis approach. A detailed description is given of the link between the relevant parameters and the density of dynamic microorganisms, motion, fluid temperature, skin friction rates, local Sherwood and Nusselt numbers, and nanocomposite volume. Gyrotactic microorganism-containing nanoparticles have potential applications in biotechnology, microfluidic devices, microbial fuel cells, and enzyme biosensors. Various features of several physical characteristics are addressed through the use of tables and graphs.

Bacterial polyynes uncovered: a journey through their bioactive properties, biosynthetic mechanisms, and sustainable production strategies.

Covering: up to 2023Conjugated polyynes are natural compounds characterized by alternating single and triple carbon-carbon bonds, endowing them with distinct physicochemical traits and a range of biological activities. While traditionally sourced mainly from plants, recent investigations have revealed many compounds originating from bacterial strains. This review synthesizes current research on bacterial-derived conjugated polyynes, delving into their biosynthetic routes, underscoring the variety in their molecular structures, and examining their potential applications in biotechnology. Additionally, we outline future directions for metabolic and protein engineering to establish more robust and stable platforms for their production.

The microwave bacteriome: biodiversity of domestic and laboratory microwave ovens.

Microwaves have become an essential part of the modern kitchen, but their potential as a reservoir for bacterial colonization and the microbial composition within them remain largely unexplored. In this study, we investigated the bacterial communities in microwave ovens and compared the microbial composition of domestic microwaves, microwaves used in shared large spaces, and laboratory microwaves, using next-generation sequencing and culturing techniques. The microwave oven bacterial population was dominated by Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes, similar to the bacterial composition of human skin. Comparison with other environments revealed that the bacterial composition of domestic microwaves was similar to that of kitchen surfaces, whereas laboratory microwaves had a higher abundance of taxa known for their ability to withstand microwave radiation, high temperatures and desiccation. These results suggest that different selective pressures, such as human contact, nutrient availability and radiation levels, may explain the differences observed between domestic and laboratory microwaves. Overall, this study provides valuable insights into microwave ovens bacterial communities and their potential biotechnological applications.

Harnessing the potential of antimicrobial peptides: current advances and future applications

Antimicrobial peptides (AMPs) represent a promising class of naturally occurring molecules with diverse structures and functions, offering a potent defense mechanism against microbial pathogens. This review explores the multifaceted role of AMPs in combating infections and their potential applications in various fields, including medicine, agriculture, and biotechnology. We discuss the mechanisms of action of AMPs, their structural diversity, modes of synthesis, and recent advancements in enhancing their stability and efficacy. Furthermore, we highlight the therapeutic potential of AMPs in treating multidrug-resistant infections, their role as alternatives to conventional antibiotics, and their applications in wound healing, immunomodulation, and drug delivery systems. Additionally, we examine the challenges associated with the clinical translation of AMPs and propose strategies to overcome these hurdles. Overall, this review underscores the importance of AMPs as versatile antimicrobial agents and emphasizes their potential to address the growing threat of antibiotic resistance.

Isolation and screening of potential lignocellulolytic microbes from Phra Nakhon Si Ayutthaya Province

Phra Nakhon Si Ayutthaya Province is an important area for rice cultivation in Thailand. However, large amounts of rice straw generated at harvest time are often burnt in the fields, causing environmental degradation and air pollution. To address this, rice straw composting by degrading microorganisms has been identified as an effective alternative for sustainable waste management, with potential applications in environmental biotechnology. For this study, 28 microorganism samples were collected from various sources in Phra Nakhon Si Ayutthaya Province, including a corrugated paper manufacturer, plant-cultivated soil, compost from dung, black soldier flies, and vermicompost. Lignocellulolytic microorganisms were screened for cellulase, xylanase, and manganese peroxidase production on agar plates and broth media using commercial and rice straw substrates. The lignocellulolytic activities were compared among the isolated and non-pathogenic microorganisms. A microbial consortium with high potential to degrade rice straw was identified, consisting of two thermophilic bacteria, Bacillus licheniformis BKT1 and BOT4, two mesophilic actinomycetes, Streptomyces ardesiacus AQ4 and An6, two thermophilic actinomycetes, Streptomyces thermoalcalitolerans APT3 and Streptomyces thermoviolaceus subsp. thermoviolaceus AQT2, and two fungi, Penicillium sp. Fh11 and Aspergillus sp. Fj6. This microbial consortium induced rapid composting of rice straw, thereby supporting sustainable agricultural waste management and reducing PM25 air pollution.

Molecular weights and optimum temperature and pH for pepsin activity of three sciaenid finfish species from the Gulf of California

By-products from finfish processing from fisheries and aquaculture are often discarded. However, the enzymatic content of viscera has potential biotechnological and industrial applications. Such is the case for the sciaenids Cynoscion othonopterus, Cynoscion xanthulus, and Cynoscion parvipinnis, which are food and game fishes from the Gulf of California and whose viscera are commonly discarded after fish dressing. In this study, optimum temperature and pH for activity, as well as molecular weights of pepsin from the stomach of C. othonopterus, C. xanthulus, and C. parvipinnis were evaluated for the first time. Pepsin molecular weights were 30, 32.1, and 32.3 kDa, respectively. The highest activity of pepsin against hemoglobin was recorded between 40 and 45?C for C. othonopterus and C. xanthulus and at 40?C for C. parvipinnis. The optimum pH was 2.0 for the three sciaenids. Biochemical characteristics were comparable to pepsins from other marine and freshwater fish species, so they could likely be used in some processes using this enzyme, like collagen extraction, fish silage production, or fish processing, among others.

Bacterial α-CAs: a biochemical and structural overview.

Carbonic anhydrases belonging to the α-class are widely distributed in bacterial species. These enzymes have been isolated from bacteria with completely different characteristics including both Gram-negative and Gram-positive strains. α-CAs show a considerable similarity when comparing the biochemical, kinetic and structural features, with only small differences which reflect the diverse role these enzymes play in Nature. In this chapter, we provide a comprehensive overview on bacterial α-CA data, with a highlight to their potential biomedical and biotechnological applications.

Nanoparticle induced fusion of lipid membranes.

Membrane fusion is crucial for infection of enveloped viruses, cellular transport, and drug delivery via liposomes. Nanoparticles can serve as fusogenic agents facilitating such membrane fusion for direct transmembrane transport. However, the underlying mechanisms of nanoparticle-induced fusion and the ideal properties of such nanoparticles remain largely unknown. Here, we used molecular dynamics simulations to investigate the efficacy of spheroidal nanoparticles with different size, prolateness, and ligand interaction strengths to enhance fusion between vesicles. By systematically varying nanoparticle properties, we identified how each parameter affects the fusion process and determined the optimal parameter range that promotes fusion. These findings provide valuable insights for the design and optimization of fusogenic nanoparticles with potential biotechnological and biomedical applications.

Analysis of Bacterial Extracellular Vesicles by Immunogold Transmission Electron Microscopy.

Bacterial extracellular vesicles (BEVs) have emerged as mediators of transkingdom communication with numerous potential biotechnological applications. As such, investigation of BEV's protein composition holds promise to uncover new biological mechanisms, such as in microbiome-host communication or pathogen infection. Additionally, bioengineering of BEV protein composition can enhance their therapeutic potential. However, accurate assessment of BEV protein cargo is limited by their nanometer size, which precludes light microscopy imaging, as well as by co-isolation of protein impurities during separation processes. A solution to these challenges is found in immunogold transmission electron microscopy (TEM), which combines antibody-based labeling with direct visualization of BEVs. Several challenges are commonly encountered during immunogold TEM analysis of BEVs, most notably inefficient antibody labeling and poor contrast. Here, we present an optimized protocol for immunogold TEM analysis of BEVs that overcomes such challenges.

Biodiversity, mechanisms, and potential biotechnological applications of minerals solubilizing extremophilic microbes: A review

The earth’s surface consists of arid, semi-arid, and hyper-arid lands, where life is profoundly challenged by harsh conditions such as temperature fluctuations, water scarcity, high levels of solar radiations, and soil salinity. The harsh environmental conditions pose serious consequences on plant survival, growth, and productivity accessibility of nutrients reduces. To cope with the harsh environments and increase plant productivity, an extremophilic microbe has attracted agriculturists and environmentalists. The extremophilic microbes, adapted to extreme environmental conditions, offer an unexploited reservoir for biofertilizers, which could provide various forms of nutrients and alleviate the stress caused by the abiotic factors in an environment-friendly manner. Worldwide, minerals solubilizing extremophilic microbes are distributed in various hotspots and belong to three domains of life including, archaea, bacteria, and eukarya. The minerals solubilizing extremophilic microbes belong to diverse phyla, namely, Ascomycota, Actinobacteria, Basidiomycota, Bacteroidetes, Crenarchaeota, Deinococcus-Thermus, Euryarchaeota, Firmicutes, and Proteobacteria. Mineral solubilizing extremophilic microbes achieve the mineral solubilization of phosphorus, potassium, zinc, and selenium by secreting special compounds such as organic acid, exopolysaccharides, and different enzymes. Consequently, extremophilic microbes are becoming increasingly important in agriculture, industries and environmental biotechnology as well, paving the way for novel sequencing technologies and “metaomics” methods, including metagenomics, metatranscriptomics, and metaproteomics. The extremophilic microbial diversity and their biotechnological application in agriculture and industrial applications will be a milestone for future needs. The present review deals with biodiversity, mechanisms and potential biotechnological applications of minerals solubilizing extremophilic microbes.