First report on molecular characterization of novel betaine aldehyde dehydrogenase from the halotolerant eubacteria, Bacillus halodurans

Extremozymes and compatible solute production potential of halophilic and halotolerant bacteria isolated from crop rhizospheric soils of Southwest Saurashtra Gujarat

Halophiles are one of the classes of extremophilic microorganisms that can flourish in environments with very high salt concentrations. In this study, fifteen bacterial strains isolated from various crop rhizospheric soils of agricultural fields along the Southwest coastline of Saurashtra, Gujarat, and identified by 16S rRNA gene sequencing as Halomonas pacifica, H. stenophila, H. salifodinae, H. binhaiensis, Oceanobacillus oncorhynchi, and Bacillus paralicheniformis were investigated for their potentiality to produce extremozymes and compatible solute. The isolates showed the production of halophilic protease, cellulase, and chitinase enzymes ranging from 6.90 to 35.38, 0.004-0.042, and 0.097-0.550 U ml-1, respectively. The production of ectoine-compatible solute ranged from 0.01 to 3.17 mg l-1. Furthermore, the investigation of the ectoine-compatible solute production at the molecular level by PCR showed the presence of the ectoine synthase gene responsible for its biosynthesis in the isolates. Besides, it also showed the presence of glycine betaine biosynthetic gene betaine aldehyde dehydrogenase in the isolates. The compatible solute production by these isolates may be linked to their ability to produce extremozymes under saline conditions, which could protect them from salt-induced denaturation, potentially enhancing their stability and activity. This correlation warrants further investigation.

Identification and quantitative chemical analysis of betaines in different organic wastes and their bioconversion composts

Global organic waste is increasing, bioconversion of organic waste arises because it can recover valuable nutrients and produce bioactive substances. Betaines are important bioactive substances in plants under environmental stress, but have received limited attention in vermicompost/larvae bioconversion compost. In this study, betaines in organic waste and vermicompost/larvae bioconversion compost were identified and quantified by HPLC-ESI-MS/MS. We observed the existence of glutamine betaine in all samples, which was first found in natural sources recently. Valine betaine was the highest among all detected betaines followed by GABA betaine, and both were rare in plants. The existence of tyrosine betaine in cow dung (CD) and vermicompost (CDV) was found, which was previously shown to be in fungi. Most importantly, we found larvae bioconversion could increase betaines by 5.56-99.75%, while vermicomposting decreased them. Bioconversion of larvae can effectively increase betaines in compost and can be used to produce potential novel functional organic fertilizers.

Deep Hypersaline Anoxic Basins as Untapped Reservoir of Polyextremophilic Prokaryotes of Biotechnological Interest

Deep-sea hypersaline anoxic basins (DHABs) are considered to be among the most extreme ecosystems on our planet, allowing only the life of polyextremophilic organisms. DHABs’ prokaryotes exhibit extraordinary metabolic capabilities, representing a hot topic for microbiologists and biotechnologists. These are a source of enzymes and new secondary metabolites with valuable applications in different biotechnological fields. Here, we review the current knowledge on prokaryotic diversity in DHABs, highlighting the biotechnological applications of identified taxa and isolated species. The discovery of new species and molecules from these ecosystems is expanding our understanding of life limits and is expected to have a strong impact on biotechnological applications.

Important roles of glycinebetaine in stabilizing the structure and function of the photosystem II complex under abiotic stresses

The molecular and physiological mechanisms of glycinebetaine stabilizing photosystem II complex under abiotic stresses are discussed, helping to address food shortage problems threatening the survival of growing population. In the backdrop of climate change, the frequency, dimensions and duration of extreme events have increased sharply, which may have unintended consequences for agricultural. The acclimation of plants to a constantly changing environment involves the accumulation of compatible solutes. Various compatible solutes enable plants to tolerate abiotic stresses, and glycinebetaine (GB) is one of the most-studied. The biosynthesis and accumulation of GB appear in numerous plant species, especially under environmental stresses. The exogenous application of GB and GB-accumulating transgenic plants have been proven to further promote plant development under stresses. Early research on GB focused on the maintenance of osmotic potential in plants. Subsequent experimental evidence demonstrated that it also protects proteins including the photosystem II complex (PSII) from denaturation and deactivation. As reviewed here, multiple experimental evidences have indicated considerable progress in the roles of GB in stabilizing PSII under abiotic stresses. Based on these advances, we've concluded two effects of GB on PSII: (1) it stabilizes the structure of PSII by protecting extrinsic proteins from dissociation or by promoting protein synthesize; (2) it enhances the oxygen-evolving activity of PSII or promotes the repair of the photosynthetic damage of PSII.