Sambhar Lake Research Articles

Morphological, hydrogeochemical and sedimentological analysis of hypersaline Sambhar Lake, India: An analog to understand evaporitic paleolake basins on Mars

In the recent decade of astrobiological exploration of the Martian surface, there has been a shift from identifying habitable environments to finding markers indicative of biological activity. It requires a prior understanding of the physical and geochemical environment of the setting to decipher whether the conditions were conducive. Generally, quiescent surroundings of lacustrine basins are considered one of the best targets for the preservation of any biological signatures. However, due to logistical limitations, the geochemical information available is mostly restricted to small areas on the surficial level (or in the subsurface in case of layered deposits or impact craters) where sufficient satellite coverage is available and, in some areas, where rovers/landers have been deployed. In this context, terrestrial lacustrine basins offer valuable insights into the environment required for the formation of the minerals observed on the Martian surface.This study was carried out within Sambhar Lake located in the arid/semiarid climatic zone within the Thar desert. It is a hypersaline playa that has undergone several cycles of desiccation and re-filling, sharing its climate-controlled history with that of several paleolakes on Mars. We conducted physicochemical analysis of the samples collected from the lake and its surrounding area and compared our results with samples from the Curiosity rover (at Gale crater) and to those of the studies carried out in basalt-rich parent settings of Iceland. Our results suggest that Sambhar Lake is a Na-Cl type brine with climate-driven hydrology. The shallow cores and rock samples indicated that the area is rich in evaporites. We propose that even the sites with different parent material may be crucial in understanding the geological evolution of paleolakes on Mars and that Sambhar is a great example to study tectono-geomorphic evolution and the climate-induced transition of a lacustrine basin to a playa. Additionally, the lake is also desirable to study extremophiles and their adaptation to changing environmental variables for future planetary missions, including but not limited to, Mars.

Hydrology Report of Sambhar Lake: A Safe Haven Past Disaster Recovery

Hydrology Report of Sambhar Lake: A Safe Haven Past Disaster Recovery

Effects of seasonal dynamics on Microalgal diversity at Sambhar Lake, India

Effects of seasonal dynamics on Microalgal diversity at Sambhar Lake, India

Bioprospecting for moderately halophilic eubacteria for potential biotechnological applications from Sambhar Lake, Rajasthan, India

Sambhar Lake an athalassohaline habitat located at 27°58′N 75°55′E, Rajasthan, India is a major source of salt production in the country. From surface lake water, soil, and shore sediments, fifty-nine moderate halophiles were isolated which were subsequently grouped according to shape, colony characteristics, and staining into twenty-two isolates. Fourier transform infrared spectroscopy profiling identifiedthese isolates as eubacterial with characteristic C=O stretching of ester functional groups. Observations further indicatedsimilarity within some Halomonasisolates indicating potential phylogenetic lineages. The FASTA sequences obtained after sequencing with universal bacterial primers were processed for phylogenetic analysis. Predominantly Gram-positive genera like Alkalibacillus, Amphibacillus, Marinococcus, Piscibacillus, Planococcus, Salinicoccus, Staphylococcusand Virgibacilluswith only two Gram-negative strains of Halomonaswere identified. The genus Amphibacilluswas recognizedfor the first time in the study of Sambhar Lake. Despite being moderately halophilic, several isolates exhibited high salt tolerance with growth in 25% salt. All isolates were mesophilic with growth observed between 18-42°C which matches the temperature profile of the region. Analysis of hydrolytic potential identified eighteen isolates as protease producers, thirteen as lipase producers, and ten as cellulase-producing strains. Further evaluation showed the dominance of C10:0, C12:0, C13:0, C14:0, C15:0, C16:0, C17:0, C18:0, C18:1 FAMEs, among which presence of C16:0 and C18:1 fatty acid indicated probable antimicrobial potentials of these strains.

Metagenomic assembled genomes indicated the potential application of hypersaline microbiome for plant growth promotion and stress alleviation in salinized soils.

The strategic implementation of metagenomic assembled genomes (MAGs) in exploring the properties and harnessing microorganisms from ecosystems like hypersaline niches has transformative potential in agriculture. This approach promises to redefine our comprehension of microbial diversity and its ecosystem roles. Recovery and decoding of MAGs unlock genetic resources, enabling the development of new solutions for agricultural challenges. Enhanced understanding of these microbial communities can lead to more efficient nutrient cycling, pest control, and soil health maintenance. Consequently, traditional agricultural practices can be improved, resulting in increased yields, reduced environmental impacts, and heightened sustainability. MAGs offer a promising avenue for sustainable agriculture, bridging the gap between cutting-edge genomics and practical field applications.

Production and characterization of an organic solvent activated protease from haloalkaliphilic bacterium Halobiforma sp. strain BNMIITR

An unusual haloalkaliphilic bacterium known as Halobiforma sp. strain BNMIITR, which was noticed to produce an extracellular alkaline protease, was found in a soil sample from Northern India's Sambhar Lake. On the generation of protease, the effects of dietary elements including nitrogen and carbon sources, amino acids, and growth conditions like temperature and pH were investigated. When low-cost agricultural by-products were employed as nitrogen sources, the manufacturing of enzymes was significantly boosted. In the present study, protease production was enhanced by 2.94 fold and 2.17 fold. By solvent precipitation and Hydrophobic interaction chromatography (HIC) on Phenyl Sepharose 6 Fast Flow matrix, the enzyme was purified 31.67 fold. It was determined that the apparent molecular mass was 21 kDa. The pH range where the enzyme was most stable was 6.0–12.0, with a temperature of 50 °C as optimum. When there was alkaline earth metals and heavy metals, protease was discovered to be active. It was evident that the enzyme was a serine type of protease because it was active in the presence of a variety of surfactants, oxidizing and reducing chemicals, and phenylmethylsulfonyl fluoride (PMSF) completely inhibited activity. Enzyme exhibited a wide range of substrate specificity. Amazingly, enzyme remained stable both in polar and nonpolar solvents. The most interesting aspect of this enzyme is enhanced activity in polar solvents like dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). It was discovered that the protease was stable and compatible with a number of widely available detergents.

Lipingzhangella rawalii sp. nov., a novel halophile isolated from Sambhar Salt Lake, Rajasthan, India.

A haloalkaliphilic actinobacterial strain LS1_29T, isolated from an inland hypersaline Sambhar Salt Lake, situated in Rajasthan, India, was subjected to taxonomic characterisation using the polyphasic approach. Cells of the strain were Gram stain positive and aerobic, having reticulate and aerial hyphae. The major fatty acids detected were iso C16:0 (38.23%), anteiso C17:0 (20.52%), iso C18:0 10 methyl (8.09%), iso C18:0 (7.74%) and iso C17:0 (7.48%). The major polar lipids identified were diphosphatidyl glycerol, phosphatidylglycerol, phosphatidylcholine and phospholipids. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that the strain belonged to the genus Lipingzhangella with the highest similarity of 94.09% to Lipingzhangella halophila EGI 80537T and formed a separate clade within the genus Lipingzhangella. The DNA G + C content of genomic DNA of strain LS1_29T was 67.99mol%. The strain showed the highest orthologous average nucleotide identity (OrthoANI) value of 72.80% and digital DNA-DNA hybridization (dDDH) value of 20.3% with Lipingzhangella halophila EGI 80537T. Based on the phenotypic, chemotaxonomic and phylogenetic characteristics, strain LS1_29T represents a novel species within the genus Lipingzhangella, for which the name Lipingzhangella rawalii sp. nov. is proposed. The type strain of the type species is LS1_29T (= KCTC 49199T = JCM 32979T = MCC 3420T).

Culture and Biofuel Producing Competence of Microalgae Dunaliella salina

In the present study halophilic microalgae Dunaliella salina obtained from Sambhar Lake, Rajasthan was cultured under controlled laboratory conditions. The biomass recovered at the end of the exponential phase was 1.25g/l dry wt. and the oil was about 22.4 % of the biomass. The oil recovered was converted into biodiesel by acid-catalyzed transesterification and the yield was 60.18%. Some specific types of Fatty acid methyl esters (FAMEs) formed were identified by GC/MS analysis. A considerable amount is accounted for four fatty acids palmitic acid (19.6%), oleic acid (25.6%), linolenic acid (27.0%) and linoleic acid (18.4%) The presence of these major fatty acids in the microalgal lipid and their transesterification gives the lipid the characteristic properties to be used for biodiesel.

Microbial community structure analysis of hypersaline niches and elucidation of their role in the biogeochemical cycling of nitrogen, sulphur and methane

Some hypersaline ecosystems exist in the form of halite, the salt deposits formed due to the evaporation of salt water. Over a period of time, the salt-saturated hypersaline lakes or seas get dried up, leading to the deposition of halite and other significant minerals. The ancient halite deposits may contain halophiles from the same era as the surrounding minerals. In the current study, the taxonomic diversity of halite deposited in the Drang Mine was analysed and compared with the microbiome of similar ecosystems, i.e., a nearby brine, Pangong Lake and Sambhar Lake. The analysis showed that Proteobacteria was the most abundant phylum across all the samples. The phylum Firmicutes exhibited the second-highest abundance in the Drang ecosystem, while Bacteroidetes were more numerous than Firmicutes in other selected niches. The lowest species richness based on the Chao I index was found in Sambhar Lake, likely because of the presence of two major extreme parameters, namely high salinity and alkaline pH. The species diversity calculated by Shannon and Simpson indices was lowest in Drang Mine, possibly because of the very high salt concentration in halite ecosystems, as also corroborated by physiochemical analysis. The beta-diversity analysis based on the Bray-Curtis matrix showed the formation of a separate cluster of Drang Mine samples, pointing towards its unique bacterial community structure as compared to other samples. The current study not only aided in the generation of baseline information about the taxonomic diversity of halite deposited in the Drang Mine but also highlighted its different bacterial community structure when compared to other similar ecosystems. It also indicated their potential role in N, S and CH4 biogeochemical cycling.

Antagonistic and Antioxidant Potential of Actinomycete Isolates from Sambhar Lake

Bacterial secondary metabolites contain a diverse spectrum of biologically active compounds, including antimicrobials and antioxidants. Harnessing these products has enabled humans to fight against various diseases. But due to the overuse of antibiotics over the past few decades, many resistant strains of microbes are emerging. Therefore, there is a need to identify new sources of antimicrobial compounds. Actinomycetes are a group of bacteria known to produce antimicrobial compounds. This investigation aimed to identify, isolate and characterize actinomycetes with antimicrobial and antioxidant activity against pathogens acquired from MTCC. Sambhar Lake has a very potential group of actinomycetes producing several secondary metabolites. The study reports the antimicrobial and antioxidant potential of different extracts of actinomycetes. The sections of the actinomycetes were tested for their antagonistic activity against five pathogenic microorganisms. Antibacterial activity was reported in all five actinomycete isolates against Bacillus subtilis-MTCC 441, Escherichia coli-MTCC-1885, and Salmonella typhi-MTCC 733 but almost negligible activity against Staphylococcus aureus-MTCC 737 and Pseudomonas aeruginosa- MTCC 424 except for ACT-14 and ACT- 11. ACT14 had the highest antibacterial activity compared to all other isolates. The antioxidant capacities of all isolated extracts were evaluated for total phenols, total antioxidant activity, total reducing power, DPPH, and ABTS assays. Section of Pseudonocardia Antarctica ACT14 showed the highest (23.89±0.96) free radical scavenging of 2, 2-diphenyl1-picrylhydrazyl (DPPH), phenolic activity (194 ± 6.05) activity. This study was conducted to identify novel actinomycetes with antimicrobial properties. The sample ACT14 was found to be a novel actinomycete (Pseudonocardia Antarctica), and this isolate showed antimicrobial activity against all the test pathogenic bacteria used in the study. The culture was optimized for antimicrobial compound production. Since many pathogens tend to acquire antibiotic resistance, this study is essential as a novel source of antimicrobials that will provide a new weapon in the fight against infectious pathogens. Further purification and characterization of this compound are underway.

Alkalihalophilic alga Picocystis salinarum SLJS6 from Sambhar Salt Lake: Potential for bicarbonate-based biomass production and carbon capture

An extremely alkalihalophilic picoalgal strain, Picocystis salinarum SLJS6 isolated from Sambhar salt lake, Rajasthan, India, was evaluated for its suitability for bicarbonate based carbon capture and biomass production. The isolate was characterized in terms of growth attributes, tolerance to salinity, high dissolved inorganic carbon (DIC) concentration and carbon fixation rates. The isolate grew robustly in a medium containing mainly Na2CO3, 50 g/L, NaHCO3, 50 g/L, NaCl, 50 g/L (salinity ≈150 ‰, DIC ≈ 1 M NaHCO3/Na2CO3) at pH 10, achieving a growth rate of 0.2282 day−1, biomass productivity of 0.498 g/L/day (>35 folds as compared to low DIC and salinity) and CO2 fixation rate of 0.729 g/L/day. Based on a rapid colorimetric method, the average total lipid content of SLJS6 was found to be 226.9 mg/g DW. Thus, P. salinarum SLJS6 is a promising candidate for bicarbonate-based CO2 capture and recycling.

Removal of Heavy Metal by Biosurfactant Producing Novel Halophilic Staphylococcus sciuri subsp. rodentium Strain SE I Isolated from Sambhar Salt Lake

AbstractThe application of halophilic biosurfactant‐producing bacteria to remove the pollutants from textile effluent was investigated in the current study. Staphylococcus sciuri subsp. rodentium strain SE I isolated from Sambhar Salt Lake, Rajasthan showed the highest emulsification activity of 65±1.2 % after 96 h of incubation with a yield of 0.189 g/l of biosurfactant. The surface tension was reduced to 46.23 mN/m±0.46 after 72 h at pH 7.0. The presence of non‐ribosomal protein sequences gave a hint of the presence of surfactin‐type lipopeptide biosurfactant and Copper Translocating P‐type ATPase enzyme sequences indicating its presence can confer resistance against heavy metals. Strain SE I showed the potential to remove heavy metals from textile effluent viz. 67 % of Cd, 64 % of Pb, 59 % of Cu, 50 % of, Cr, and 33 % of Ni after 7 days of treatment as well exhibited decolorization of dyes ranging from 61 %±0.15 to 95 %±1.03, respectively. Based on the research findings, it is reasonable to conclude that surfactin biosurfactant extracted from S. sciuri subsp. rodentium strain SE I can be an alternative biosorbent and function as a bioremediation agent.

Halophilic and Halotolerant Actinomycetes of Sambhar Salt Lake, India: Screening and Optimization of Cellulolytic Activity

Actinomycetes are Gram-positive filamentous bacteria well known for the production of bioactive compounds. Recently, many halophilic habitats have been explored for isolation of actinomycetes that exhibit biotechnological potentials. In this investigation, a saline habitat of Rajasthan, Sambhar Salt Lake (SSL) was selected to study the actinomycetes population and Carboxy Methyl Cellulase (CMCase) production by native isolates. A total of sixteen actinomycete isolates, halotolerant and moderately halophilic, were obtained using culture-dependent methods and characterized morphologically and biochemically. They were identified as members of Streptomyces, Nocardiopsis, Pseudonocardia, Saccharospolyspora, and Microbispora. Streptomyces was the most dominating genus, followed by Nocardiopsis. Agar plate assay was used for screening the isolates for CMCase production. Thirteen were found to produce the enzyme, apparent by hydrolysis observed on media plates. The highest relative activity of 22.04 was shown by isolate SSL 14 identified as Nocardiopsis sp. by 16S rDNA sequencing studies and thus selected for further optimization studies. Maximum enzyme (1.08 ± 0.09 U/ml) was produced using medium containing Carboxy Methyl Cellulose (Carbon source) and yeast extract (nitrogen source) at 12% NaCl and pH 9.0, incubated at 30 °C for 96 h. Maximum CMCase production at high salt concentration and pH suggests that Nocardiopsis SSL 14 can be used for industrial processes that operate under excessive saline and alkaline conditions.

Deciphering the molecular diversity of related halophilic Bacillus sp. isolated from Sambhar Lake and the functional characterizations of surfactin

AbstractThe Sambhar Salt Lake in Rajasthan, India, offers a unique opportunity to explore halophilic surfactin‐producing microorganisms with industrial application. The phylogenetic study, comparative genomics combined with chemotaxonomic research provided insight into the interspecies relativeness of Bacillus sp. Considering the nonribosomal protein sequences (NRPS), Bacillus haynesii strain SAII strain and Bacillus swezeyi strain SEIII showed a high degree of conservation. In silico studies of the isolated Bacillus sp. confirmed the presence of NRPS indicating the presence of surfactin‐type lipopeptide biosurfactants. Structural investigation using Fourier transform infrared spectroscopy, liquid quadrupole triple quadrupole mass spectrometry, 1H Nuclear mass resonance of the crude biosurfactant revealed further similarities among these two Bacillus species. Methyl esters of the crude biosurfactant indicated high likeliness among them and indicated the presence of pentadecanoic acid and tetradecanoic acid as the crucial fatty acids. Enhanced recovery of oil from contaminated sand using 100% crude biosurfactant ranged from 20% ± 0.05 to 69.20% ± 1.22. This opens the door to a bright future for understanding the molecular diversity of closely related halophilic Bacillus sp. and the potential use of the extracted biosurfactants for bioremediation of contaminants.

Genome Sequence of Salipaludibacillus sp. Strain CUR1, Isolated from an Alkaline-Saline Lake in Rajasthan, India.

ABSTRACTWe report the complete genome sequence of Salipaludibacillus sp. strain CUR1, which was isolated from Sambhar Lake (a soda lake) in Rajasthan, India. The whole-genome sequencing of this strain has been done to explore the industrially important hydrolytic and extracellular enzymes that can be active under high-salt and high-pH conditions.

Monitoring migratory birds of India's largest shallow saline Ramsar site (Sambhar Lake) using geospatial data for wetland restoration.

Globally, saline lakes occupy about 23% by area, and 44% by volume. Importantly, these lakes might desiccate by 2025 due to agricultural diversion, illegal encroachment, or modify due to pollution, and invasive species. India’s largest saline lake, Sambhar is currently shrinking at a phenomenal rate of 4.23% every decade due to illegal saltpan encroachments. This study aims to identify the trend of migratory birds and monthly wetland status. Birds’ survey was conducted for 2019, 2020 and 2021, and combined it with literature data of 1994, 2003, and 2013, for understanding their visiting trends, feeding habits, migratory and resident birds ratio, along with ecological diversity index analysis. Normalized Difference Water Index (NDWI) was scripted in Google Earth Engine. Results state that lake has been suitable for 97 species. Highest NDWI values was 0.71 in 2021 and lowest 0.008 in 2019. Notably, the decreasing trend of migratory birds coupled with decreasing water level indicates the dubious status for its existence. If these causal factors are not checked, it might completely desiccate. Authors recommend a few steps that might help conservation. Least, the cost of restoration might exceed the revenue generation.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11273-022-09875-3.

Natronococcus pandeyae sp. nov., a Novel Haloarchaeon from Sambhar Salt Lake

A halophilic archaeon, designated strain LS1_42T, was isolated from Sambhar Salt Lake, Rajasthan, India. Cells were non-motile, coccoid, Gram-stain-variable and present in irregular clusters with light pink pigmented colonies. The strain was strictly aerobic and able to grow without Mg2+. Growth of the strain LS1_42T was observed at 25-45°C, pH 7.0-11.0 and NaCl concentrations of 10-35% (w/v). The nearest phylogenetic neighbor of strain LS1_42T was Natronococcus amylolyticus Ah-36T based on 16S rRNA and rpoB' genes with similarity of 95.4% and 91.9%, respectively. Phylogenetic analysis based on 16S rRNA gene, rpoB' gene and whole-genome sequences indicate that the strain LS1_42T belongs to the genus Natronococcus and is closely related to N. amylolyticus. The genome size was 5.38Mb with 98.9% completeness. The DNA G + C content of the strain LS1_42T was 63.0mol%. The average nucleotide identity, average amino acid identity and DNA-DNA hybridization values between LS1_42T and N. amylolyticus Ah-36T were 81.3%, 77.7% and 24.8%, respectively. The major polar lipids detected were phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester. On the basis of phenotypic, chemotaxonomic and genome-based analysis, strain LS1_42T represents a novel species within the genus Natronococcus, for which the name Natronococcus pandeyae sp. nov. is proposed. The type strain is LS1_42T (MCC 3654T = JCM 33003T = KCTC 4280T = CGMCC 1.16738T).

Culture-Independent Exploration of the Hypersaline Ecosystem Indicates the Environment-Specific Microbiome Evolution.

Sambhar Salt Lake, situated in the state of Rajasthan, India is a unique temperate hypersaline ecosystem. Exploration of the salt lake microbiome will enable us to understand microbiome functioning in nutrient-deprived extreme conditions, as well as enrich our understanding of the environment-specific microbiome evolution. The current study has been designed to explore the Sambhar Salt Lake microbiome with a culture-independent multi-omics approach to define its metagenomic features and prevalent metabolic functionaries. The rRNA feature and protein feature-based phylogenetic reconstruction synchronously (R = 0.908) indicated the dominance of the archaea (Euryarchaeota) and bacteria (Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria). Metabolic reconstruction identified selective enrichment of the protein features associated with energy harvesting and stress tolerance (osmotic, oxidative, metal/metalloid, heat/cold, antibiotic, and desiccation). Metabolites identified with metabolome analysis confirmed physiological adaptation of the lake microbiome within a hypersaline and nutrient-deprived environment. Comparative metagenomics of the 212 metagenomes representing freshwater, alkaline, and saline ecosystem microbiome indicated the selective enrichment of the microbial groups and genetic features. The current study elucidates microbiome functioning within the nutrient-deprived harsh ecosystems. In summary, the current study harnessing the strength of multi-omics and comparative metagenomics indicates the environment-specific microbiome evolution.

Spatio-temporal modelling for the evaluation of an altered Indian saline Ramsar site and its drivers for ecosystem management and restoration.

Saline lakes occupy 44% and 23% of the volume and area of all lakes that are tending to suffer from extended dryness, reduced hydro period, or complete desiccation by 2025. The current study is conducted on Sambhar Salt Lake, the largest inland saline Ramsar, site of India, contributing to 9.86% of total salt production. The lake is under threat due to illegal salt pan encroachment, losing brine worth 300 million USD. The objective was to identify the key drivers that affect the lake at a landscape level. Geospatial modelling was conducted for 96 years (1963-2059) at a decadal scale, integrating ground data (birds-soil-water). Land Use Land Cover (LULC) classification was conducted using CORONA aerial imagery of 1963, along with Landsat imageries, using supervised classification for 1972, 1981, 1992, 2009, and 2019, and future prediction for 2029, 2039, 2049, and 2059. Further, images were classified into 8 classes that include the Aravali hills, barren land, saline soil, salt crust, salt pans, wetland, settlement, and vegetation. Past trends show a reduction of wetland from 30.7 to 3.4% at a constant rate (4.23%) to saline soil, which subsequently seemed to increase by 9.3%, increasing thereby the barren land by 4.2%; salt pans by 6.6%, and settlement by 1.2% till 2019. Future predictions show loss of 40% wetland and 120% of saline soil and net increase in 30% vegetation, 40% settlement, 10% salt pan, 5% barren land, and a net loss of 20%, each by Aravali hills and salt crust. Additionally, the ground result shows its alteration and reduction of migratory birds from 3 million to 3000. In the light of UN Decade on Ecosystem Restoration (2021-2030), restoration strategies are suggested; if delayed, more restoration capital may be required than its revenue generation.

Evaluation of UV-B protection efficiency of mycosporine like amino acid extracted from the cyanobacteria Anabaenopsis sp. SLCyA isolated from a hypersaline lake

MAAs are natural UV-protectant molecules produced by many marine organisms including cyanobacteria. In the present study five different cyanobacterial strains were isolated from hypersaline Sambhar Lake, India. The isolated cyanobacterium Anabaenopsis sp. SLCyA was able to produce large quantity of MAA (0.1 mg/g dry weight) when exposed to photosynthetically active radiation (PAR) and ultraviolet radiation-B (UV-B) until 48 h. The produced MAA was identified as Shinorine showed the absorption maximum at 334 nm. This MAA was able to provide significant protection to E. coli ATCC 25922 against UV-B radiation and 83.5% of the cells survived even after 20 min of exposure.