Appropriate characterization of reservoir properties and investigation of their effect on microbial enhanced oil recovery through simulated laboratory studies.

Appropriate characterization of reservoir properties and investigation of the effect of these properties on microbial metabolism and oil recovery under simulated reservoir conditions can aid in development of a sustainable microbial enhanced oil recovery (MEOR) process. Our present study has unveiled the promising potential of the hyperthermophilic archaeon, identified as Thermococcus petroboostus sp. nov. 101C5, to positively influence the microenvironment within simulated oil reservoirs, by producing significant amounts of metabolites, such as biosurfactants, biopolymers, biomass, acids, solvents, gases. These MEOR desired metabolites were found to cause a series of desirable changes in the physicochemical properties of crude oil and reservoir rocks, thereby enhancing oil recovery. Furthermore, our study demonstrated that the microbial activity of 101C5 led to the mobilization of crude oil, consequently resulting in enhanced production rates and increased efficiency in simulated sand pack trials. 101C5 exhibited considerable potential as a versatile microorganism for MEOR applications across diverse reservoir conditions, mediating significant light as well as heavy oil recovery from Berea/carbonaceous nature of rock bearing intergranular/vugular/fracture porosity at extreme reservoir conditions characterized by high temperature (80-101 °C) and high pressure (700-1300 psi). Core flood study, which truly mimicked the reservoir conditions demonstrated 29.5% incremental oil recovery by 101C5 action from Berea sandstone at 900 psi and 96 °C, underscoring the potential of strain 101C5 for application in the depleted high temperature oil wells.

Unveiling the Probiotic Potential of Streptococcus thermophilus MCC0200: Insights from In Vitro Studies Corroborated with Genome Analysis.

Streptococcus thermophilus is widely used as a starter culture in the dairy industry and has garnered attention as a beneficial bacterium owing to its health-promoting functionalities in humans. In this study, the probiotic potential of S. thermophilus MCC0200 isolated from a dairy product was investigated through a combinatorial approach of in vitro and in silico studies. MCC0200 demonstrated the ability to survive harsh gastrointestinal (GI) transit, adhere to intestinal mucosa and exert health-promoting traits in in vitro studies. These findings were corroborated with in silico evidence, wherein, MCC0200 genome harboured genes associated with tolerance to GI conditions, intestinal adhesion and colonization. Genome mapping also highlighted the ability of MCC0200 to produce compounds advantageous for the host (folate, bacteriocins), to release antioxidant enzymes that can quench the free radicals (superoxide dismutase, NADH peroxidase), and to metabolize food components that can be harmful to sensitive people (lactose). MCC0200 also demonstrated a positive effect on reducing cholesterol levels, proving to be a potential candidate for food and pharmaceutical applications. The absence of transmissible antibiotic resistance genes and virulence genes underscored the generally regarded as safe (GRAS) nature of MCC0200. This study explored the potential of Streptococcus thermophilus for its probable applications as a probiotic beyond the dairy industry.

Genomics and simulated laboratory studies reveal Thermococcus sp. 101C5 as a novel hyperthermophilic archaeon possessing a specialized metabolic arsenal for enhanced oil recovery.

Laboratory evaluation of hyperthermophiles with the potential for Enhanced Oil Recovery (EOR) is often hampered by the difficulties in replicating the in situ growth conditions in the laboratory. In the present investigation, genome analysis was used to gain insights into the metabolic potential of a hyperthermophile to mobilize the residual oil from depleting high-temperature oil reservoirs. Here, we report the 1.9 Mb draft genome sequence of a hyperthermophilic anaerobic archaeon, Thermococcus sp. 101C5, with a GC content of 44%, isolated from a high-temperature oil reservoir of Gujarat, India. 101C5 possessed the genetic arsenal required for adaptation to harsh oil reservoir conditions, such as various heat shock proteins for thermo-adaptation, Trk potassium uptake system proteins for osmo-adaptation, and superoxide reductases against oxidative stress. Microbial Enhanced Oil Recovery (MEOR) potential of the strain was established by ascertaining the presence of genes encoding enzymes involved in the production of the metabolites such as hydrogen, bio-emulsifier, acetate, exopolysaccharide, etc. Production of these metabolites which pressurize the reservoir, emulsify the crude oil, lower the viscosity and reduce the drag, thus facilitating mobilization of the residual oil was experimentally confirmed. Also, the presence of crude oil degradative genes highlighted the ability of the strain to mobilize heavy residual oil, which was confirmed under simulated conditions in sand-pack studies. The obtained results demonstrated additional oil recoveries of 42.1% and 56.5% at 96 °C and 101 °C, respectively, by the strain 101C5, illustrating its potential for application in high-temperature oil reservoirs. To our best knowledge, this is the first report of genome analysis of any microbe assessed for its suitability for MEOR from the high-temperature oil reservoir.

Draft Genome Sequence of Permafrost Bacterium Nesterenkonia sp. Strain PF2B19, Revealing a Cold Adaptation Strategy and Diverse Biotechnological Potential.

Nesterenkonia sp. strain PF2B19, a psychrophilic bacterium, was isolated from 44,800-year-old permafrost. The draft genome sequence of this strain revealed the presence of genes involved in the production of cold active enzymes, carotenoid biosynthesis, fatty acid biosynthesis, and resistance to heavy metals. These results show the immense potential of the strain.

Insights into the Psychrophilic and Sea Ice-Specific Lifestyle of Marinobacter sp. Strain AC-23: a Genomic Approach.

Marinobacter sp. strain AC-23 was isolated from Kongsfjorden in the Arctic. Here, we report the first draft genome sequence of a putative novel species of the genus Marinobacter comprising 4,149,715 bp, with a mean G+C content of 54.4%. The draft genome sequence will aid in understanding the psychrophilic and sea ice-specific lifestyle.

Microbial communities associated with Antarctic snow pack and their biogeochemical implications.

Snow ecosystems represent a large part of the Earth's biosphere and harbour diverse microbial communities. Despite our increased knowledge of snow microbial communities, the question remains as to their functional potential, particularly with respect to their role in adapting to and modifying the specific snow environment. In this work, we investigated the diversity and functional capabilities of microorganisms from 3 regions of East Antarctica, with respect to compounds present in snow and tested whether their functional signature reflected the snow environment. A diverse assemblage of bacteria (Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, Deinococcus-Thermus, Planctomycetes, Verrucomicrobia), archaea (Euryarchaeota), and eukarya (Basidiomycota, Ascomycota, Cryptomycota and Rhizaria) were detected through culture-dependent and -independent methods. Although microbial communities observed in the three snow samples were distinctly different, all isolates tested produced one or more of the following enzymes: lipase, protease, amylase, ß-galactosidase, cellulase, and/or lignin modifying enzyme. This indicates that the snow pack microbes have the capacity to degrade organic compounds found in Antarctic snow (proteins, lipids, carbohydrates, lignin), thus highlighting their potential to be involved in snow chemistry.

Genome Characteristics of a Novel Type I Methanotroph (Sn10-6) Isolated from a Flooded Indian Rice Field.

Flooded rice fields are important sources of atmospheric methane. Aerobic methanotrophs living in the vicinity of rice roots oxidize methane and act as environmental filters. Here, we present genome characteristics of a gammaproteobacterial methanotroph, isolate Sn10-6, which was isolated from a rice rhizosphere of a flooded field in India. Sn10-6 has been identified as a member of a putative novel genus and species within the family Methylococcaceae (Type I methanotrophs). The draft genome of Sn10-6 showed pathways for the following: methane oxidation, formaldehyde assimilation (RuMP), nitrogen fixation, conversion of nitrite to nitrous oxide, and other interesting genes including the ones responsible for survival in the rhizosphere environment. The majority of genes found in this genome were most similar to Methylovulum miyakonese which is a forest isolate. This draft genome provided insight into the physiology, ecology, and phylogeny of this gammaproteobacterial methanotroph.

Deciphering Community Structure of Methanotrophs Dwelling in Rice Rhizospheres of an Indian Rice Field Using Cultivation and Cultivation-Independent Approaches.

Methanotrophs play a crucial role in filtering out methane from habitats, such as flooded rice fields. India has the largest area under rice cultivation in the world; however, to the best of our knowledge, methanotrophs have not been isolated and characterized from Indian rice fields. A cultivation strategy composing of a modified medium, longer incubation time, and serial dilutions in microtiter plates was used to cultivate methanotrophs from a rice rhizosphere sample from a flooded rice field in Western India. We compared the cultured members with the uncultured community as revealed by three culture-independent methods. A novel type Ia methanotroph (Sn10-6), at the rank of a genus, and a putative novel species of a type II methanotroph (Sn-Cys) were cultivated from the terminal positive dilution (10(-6)). From lower dilution (10(-4)), a strain of Methylomonas spp. was cultivated. All the three culture-independent analyses, i.e., pmoA clone library, terminal restriction fragment length polymorphism (T-RFLP), and metagenomics approach, revealed the dominance of type I methanotrophs. Only metagenomic analysis showed significant presence of type II methanotrophs, albeit in lower proportion (37 %). All the three isolates showed relevance to the methanotrophic community as depicted by uncultured methods; however, the cultivated members might not be the most dominant ones. In conclusion, a combined cultivation and cultivation-independent strategy yielded us a broader picture of the methanotrophic community from rice rhizospheres of a flooded rice field in India.

Draft genome of Elstera litoralis, a freshwater epilithic biofilm associated bacterium from littoral zone of Lake Constance.

Elstera litoralis, is a Rhodospirillaceae member which was isolated from the littoral zone of Lake Constance from a stone biofilm using diatom extracellular polymeric substances (EPS) as C source. We present here the draft genome of E. litoralis which has a genome size of 3.83 Mb and 61.2% G+C content. Genome analysis indicated utilization of multiple C substrates explaining its heterotrophic lifestyle as a bacterium present in natural biofilms. Further comparative genome analysis of Elstera with other members of Rhodospirillaceae would be helpful to understand the evolutionary relationships and divergence of hydrobacteria from terrabacteria.

Draft genome of Cryobacterium sp. MLB-32, an obligate psychrophile from glacier cryoconite holes of high Arctic.

Obligate psychrophilic, Cryobacterium sp. MLB-32, was isolated from cryoconite holes of high Arctic glaciers. Here, we report the first draft genome sequence of the putative novel species of the genus Cryobacterium, providing opportunities for biotechnological and agricultural exploitation of its genome features.