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Interconnection between PHA and Stress Robustness of Bacteria
Published in Martin Koller, The Handbook of Polyhydroxyalkanoates, 2020
Stanislav Obruca, Petr Sedlacek, Iva Pernicova, Adriana Kovalcik, Ivana Novackova, Eva Slaninova, Ivana Marova
Extreme thermophiles producing PHA include bacteria of the genus Thermus thermophilus. The cultivation temperature is 75°C and when sodium gluconate (1.5% w/v) or sodium octanoate (10 mM) are used as solo carbon sources, Thermus thermophilus can produce PHA at approximately 35 to 40% dry weight of biomass. By gas chromatography analysis, the production on gluconate was found to give a polyester composed mainly of 3-hydroxydecanoate (3HD) with the molar fraction of up to 64 mol-%. Other components in polyester, in addition to 3HD, were 3-hydroxyoctanoate (3HO), 3-hydroxyvalerate (3HV) and 3-hydroxybutyrate (3HB). However, the polyester produced when grown on octanoate as the only carbon source was composed of more than one monomer unit, namely 35.4 mol-% 3-hydroxyundecanoate (3HUD), 24.5 mol-% 3HB, 14.6 mol-% 3HD, 12.3 mol-% 3-hydroxynonanoate (3HN) and 7.8 mol-% 3-hydroxydodecanoate [33].
Esterases and Their Industrial Applications
Published in Pankaj Bhatt, Industrial Applications of Microbial Enzymes, 2023
Hamza Rafeeq, Asim Hussain, Ayesha Safdar, Sumaira Shabbir, Muhammad Bilal, Farooq Sher, Marcelo Franco, Hafiz M. N. Iqbal
Plants, animals, and microorganisms have been recognized as a source for esterases production (Figure 8.1). The expenses of cultivation and maintenance are inexpensive and simple to adjust; thus, microorganism enzymes are preferred. Either intrinsically or through induction, all species of microbes produce esterases. Diverse bacterial species are usually purchased or isolated from cultural collections for esterase biosynthesis. Microbes are collected from the cheese area, oil-polluted municipal waste, or sea squid to be used in the production of esterase (Ranjitha et al., 2009; Sayali et al., 2013). A new technique for esterase metagenome testing was applied, and the source of esterase originated through metagenomic libraries in many circumstances (Fan et al., 2012). The sequence automatic processes and shotgun cloning have been responsible for the launching of several genome projects that include a great deal of genetic data. To date, the Genome Atlas Database has included 1,078 bacterial genomes and 82 archaea (Hallin and Ussery, 2004). Selected results reveal a lot of enzymes, which were subsequently cloned, overexpressed, and purified for biochemical characterization by genome mining for new genes through homology with identified lipase and esterases. Thus, a few lipolytic enzymes were cloned and expressed in mesophilic hosts from Thermus thermophilus HB27, whose genome is fully sequenced and accessible publicly (Henne et al., 2004). Extremely thermal stability and a very high behavior at mesophilic temperatures were obtained with a significant proprietary reciprocal esterase, a significant fact of its thermophilic nature (López-López et al., 2010).
Functional Metagenomics
Published in Vineet Kumar, Vinod Kumar Garg, Sunil Kumar, Jayanta Kumar Biswas, Omics for Environmental Engineering and Microbiology Systems, 2023
Kripa Pancholi, Anupama Shrivastav
The global increase in population results in an increase in the productivity of medical care facilities and medicines to fight specific diseases, which has exponentially increased the utility of nutritional products. The chemical, pharmaceutical, and nutraceutical industries cannot sufficiently fulfil the demand. Therefore, the booming area of biotechnology and microbiology industries uses microorganisms to produce antibiotics, enzymes, and other organic and bioactive compounds. Metagenomics along with other biotechnological processes favours the industrial production of chemicals, nutraceuticals, biofuels, pharmaceuticals, etc., which plays a major role in bringing back the bioactive molecules and enzymes that were earlier not utilized (Kumar et al. 2021). Metagenomic libraries help in screening such enzymes and metabolites depending on their activities. In functional metagenomics, the cultural mix is extracted from the environment; the DNA comes up with gene libraries through shotgun sequencing, where E. coli is used as the cloning host (Snipen et al. 2021). Now when the clones are formed, they are treated with antibiotics having enough concentration to kill the host except for the host having a resistance gene and are classified taxonomically at the end. The only purpose of taxonomic classification is to find the exact species of origin from the environment so that the researchers can investigate the diversities in the microbial community. The classification method allows the study of the relationship between host stages or environmental changes and the species diversity of microbial communities (Awasthi et al. 2020). The functional metagenomics along with sequence-based screening overcomes the limitation of small size, which does not provide enough information regarding resistance gene and the initial host organism. Here, clones growing on antibiotics were selected along with small DNA libraries from metagenomic DNA, which proves that genetic elements have the resistance gene. The functional metagenomics is the only metagenomic screening that allows the isolation of antibiotic resistance genes on the condition of expression of gene resistance. The E. coli is the most common cloning host, and when it is intrinsically resistant to antibiotics, functional screening cannot be shown proving the false negatives. The selection of expression host becomes mandatory for metagenomics for the expression of the gene; E. coli is sufficient for promoter recognition and translation initiation, but some strains do not efficiently express due to various reasons. During special conditions such as high temperature or active conditions, this issue becomes worst for protein expression, so alternative host expression is done where thermophilic bacterium such as Thermus thermophilus is used. It helps in the detection of thermozymes (DeCastro et al. 2016).
Production, purification, characterization, and applications of α-galactosidase from Bacillus flexus JS27 isolated from Manikaran hot springs
Published in Preparative Biochemistry & Biotechnology, 2023
Sonu Bhatia, Navneet Batra, Jagtar Singh
Various habitats have been explored for commercial production of novel α-galactosidases exhibiting properties like thermostability, pH stability, resistance toward proteases, high yield potential, variable substrate specificity, elevated catalytic efficiency, and immense synergistic capacity.[7] Thermostable enzymes from thermophilic microorganisms exhibit good tolerance to harsh industrial processes hence they are suitable at high processing temperatures in industries.[8–10] Thermostable α-galactosidases from extremophilic bacteria have been isolated and characterized from Thermotoga maritima, genus Geobacillus, Meiothermus taiwanensis, Bacillus stearothermophilus, Thermus thermophilus, etc.[11–13]