Browsing by Author "Rathore, Parikshita"

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    Co-occurrence and patterns of phosphate solubilizing, salt and metal tolerant and antibiotic-resistant bacteria in diverse soils
    (Springer Science and Business Media Deutschland GmbH, 2021-06-24T00:00:00) Rathore, Parikshita; Joy, Sherina Sara; Yadav, Radheshyam; Ramakrishna, Wusirika
    Soil is a treasure chest for beneficial bacteria with applications in diverse fields, which include agriculture, rhizoremediation, and medicine. Metagenomic analysis of four soil samples identified Proteobacteria as the dominant phylum (32�52%) followed by the phylum Acidobacteria (11�21% in three out of four soils). Bacteria that were prevalent at the highest level belong to the genus Kaistobacter (8�19%). PICRUSt analysis predicted KEGG functional pathways associated with the metagenomes of the four soils. The identified pathways could be attributed to metal tolerance, antibiotic resistance and plant growth promotion. The prevalence of phosphate solubilizing bacteria (PSB) was investigated in four soil samples, ranging from 26 to 59% of the total culturable bacteria. The abundance of salt-tolerant and metal-tolerant bacteria showed considerable variation ranging from 1 to 62% and 4�69%, respectively. In comparison, the soil with the maximum prevalence of temperature-tolerant and antibiotic-resistant bacteria was close 30%. In this study, the common pattern observed was that PSB were the most abundant in all types of soils compared to other traits. Conversely, most of the isolates, which are salt-tolerant, copper-tolerant, and ampicillin-resistant, showed phosphate solubilization activity. The sequencing of the partial 16S-rRNA gene revealed that PSB belonged to Bacillus genera. � 2021, King Abdulaziz City for Science and Technology.
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    Overview of extraction of astaxanthin from Haematococcus pluvialis using CO2 supercritical fluid extraction technology vis-a-vis quality demands
    (Elsevier, 2021-04-19T00:00:00) Saini, Khem Chand; Yadav, Digvijay Singh; Mehariya, Sanjeet; Rathore, Parikshita; Kumar, Bikash; Marino, Tiziana; Leone, Gian Paolo; Verma, Pradeep; Musmarra, Dino; Molino, Antonio
    Microalgae biomass have been used as a source of nutrient-rich food, feed, and health-promoting compounds. Among the several commercially available microalgae, Haematococcus pluvialis is the most abundant source of natural astaxanthin (3, 3'-dihydroxy-?, ?-carotene-4, 4'-dione), which is considered as �super antioxidant.� Therefore natural astaxanthin produced by H. pluvialis has a higher antioxidant capacity than the synthetic sources, which reduces oxidative stress and free radicals and helps the human body to maintain a healthy state. However, H. pluvialis contains astaxanthin inside the cells, which need to be extracted using nontoxic extraction technologies for different application. Among the different available extraction technologies, supercritical fluid extraction (SFE) is a modern technology with increasing applications in pharmaceutical and nutraceutical sector. The most frequently employed supercritical solvent in food and natural product processing is carbon dioxide (CO2) due to its low critical temperature and pressure while considered as nontoxic extraction solvent. Therefore, nowadays, supercritical carbon dioxide (SC-CO2) is considered as a new substitute for complete extraction of natural compounds from different matrices. However, the extraction efficiency and purity of astaxanthin in the extract are influenced by different operative conditions such as the extraction pressure, temperature, time, and use of cosolvent. Hence the optimum operative condition of SC-CO2 extraction could enhance the extraction yields of astaxanthin and of its purity the extract. Therefore present chapter summarizes the effects of several extraction parameters on SC-CO2 extraction of astaxanthin from H. pluvialis, which could serve as benchmark for future development of SC-CO2 extraction technology and its commercial implementation in pharmaceutical and nutraceutical sector. � 2021 Elsevier Inc.
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    Plant growth promoting rhizobacteria, arbuscular mycorrhizal fungi and their synergistic interactions to counteract the negative effects of saline soil on agriculture: Key macromolecules and mechanisms
    (MDPI AG, 2021-07-14T00:00:00) Sagar, Alka; Rathore, Parikshita; Ramteke, Pramod W.; Ramakrishna, Wusirika; Reddy, Munagala S.; Pecoraro, Lorenzo
    Soil saltiness is a noteworthy issue as it results in loss of profitability and development of agrarian harvests and decline in soil health. Microorganisms associated with plants contribute to their growth promotion and salinity tolerance by employing a multitude of macromolecules and pathways. Plant growth promoting rhizobacteria (PGPR) have an immediate impact on improving profitability based on higher crop yield. Some PGPR produce 1-aminocyclopropane-1-carboxylic (ACC) deami-nase (EC 4.1.99.4), which controls ethylene production by diverting ACC into ?-ketobutyrate and ammonia. ACC deaminase enhances germination rate and growth parameters of root and shoot in different harvests with and without salt stress. Arbuscular mycorrhizal fungi (AMF) show a symbiotic relationship with plants, which helps in efficient uptake of mineral nutrients and water by the plants and also provide protection to the plants against pathogens and various abiotic stresses. The dual inoculation of PGPR and AMF enhances nutrient uptake and productivity of several crops compared to a single inoculation in both normal and stressed environments. Positively interacting PGPR + AMF combination is an efficient and cost-effective recipe for improving plant tolerance against salinity stress, which can be an extremely useful approach for sustainable agriculture. � 2021 by the authors. Licensee MDPI, Basel, Switzerland.