A New Bacterial Strain Producing Both of the Surfactin and Fengycin Lipopeptide Biosurfactant with Strong Emulsifications on Crude Oil.

A new lipopeptide-producing strain Cytobacillus sp. R3-1 was isolated from the production water of the Daqing oilfield in China and identified based on 16S rRNA gene sequence analyses. The strain R3-1 is capable of simultaneously producing both of the surfactin and fengycin, the two major families of the lipopeptide biosurfactant.

Pattern and extent of intrahepatic infiltration of perihilar cholangiocarcinoma - A case-control study based on liver panoramic digital pathology.

Background: The extent of intrahepatic infiltration of perihilar cholangiocarcinoma (PHCC) remains unclear. This research aimed to explore the pattern and extent of intrahepatic infiltration of PHCC to guide surgical treatment and pathological research.

Materials And Methods: This study included 62 patients diagnosed with PHCC who underwent major hepatectomy.

Safety and benefit of modified mesohepatectomy in the treatment of bilobar involvement congenital biliary dilatation.

Background: The diseased bile duct in bilobar congenital biliary dilatation is extensive and often requires major hepatectomy or liver transplantation associated with a higher risk. We aimed to evaluate the safety and benefit of modified mesohepatectomy, in comparison with trisectionectomy, to treat bilobar congenital biliary dilatation.

Methods: This study included 28 patients with type IV and V bilobar congenital biliary dilatation.

Structural diversity and applications of lipopeptide biosurfactants as biocontrol agents against phytopathogens: A review.

Amphipathic compounds known as biosurfactants are able to reduce surface and interfacial tensions. These substances produced by microbial organisms perform the same functions as chemical surfactants with several enhancements, the most significant of which is biocontrol activity. Lipopeptide is one of the five biosurfactants from natural resources and is identified as the best alternative for chemical surfactants and the major topic of interest for both scientific and industrial communities due to their increasingly growing potential applications in biological and commercial fields.

Structural and compositional diversity of biosurfactants produced by a novel strain of Sporosarcina luteola ME44 from oil reservoir.

The urealytically active microorganism Sporosarcina luteola induces the precipitation of metals, which has attracted attention in biomineralization, bioremediation, and industrial waste recycling. Herein, we report a novel biosurfactant-producing strain of S. luteola ME44 isolated from Chinese Oilfield.

A new biosurfactant-producing strain, ME46, isolated from an oil field in China.

The genus contains twelve species significant in the synthesis of cellulose-degrading enzymes and phenylalanine dehydrogenase, isolated mainly from marine sedimentary environments. Here, we report a new biosurfactant-producing strain, ME46, isolated from Daqing oil field in China. The biosurfactant extracted from Strain ME46 was determined as surfactin, one of the representative families of lipopeptide biosurfactants.

Structural Diversity of the Lipopeptide Biosurfactant Produced by a Newly Isolated Strain, ME63.

The genus is active in degradation of hydrocarbons in thermophilic and facultative environments since it was first reported in 1920. Here, we report a new strain, ME63, isolated from an oilfield with the ability of producing the biosurfactant. The composition, chemical structure, and surface activity of the biosurfactant produced by ME63 were investigated by using a combination of the high-performance liquid chromatography, time-of-flight ion mass spectrometry, and surface tensiometer.

Quantitative determination of rhamnolipid using HPLC-UV through carboxyl labeling.

Rhamnolipid, as a low-toxic, biodegradable and environmentally friendly biosurfactant, has broad application prospects in many industries. However, the quantitative determination of rhamnolipid is still a challenging task. Here, a new sensitive method for the quantitative analysis of rhamnolipid based on a simple derivatization reaction was developed.

Adsorption Kinetics of Biosurfactant Surfactin at the -Hexadecane/Aqueous Solution Interface.

Surfactin is a typical kind of biosurfactant with a large diversity of structure, and its molecular structure is expected to play a crucial role in its adsorption dynamics. Adsorption kinetics of surfactin homologues at the -hexadecane/aqueous solution interface is studied using a droplet-based microfluidic method. Molecular dynamics simulations are performed to illustrate the dependence of adsorption energy on the surfactin structure.

Characteristics of microbiota, core sulfate-reducing taxa and corrosion rates in production water from five petroleum reservoirs in China.

Microbial diversity and activities in petroleum reservoir systems can be altered by water-flooding operation, but the current understanding of the mechanism for such changes in microbial composition characteristics and community is inadequate. In this study, microbial communities especially functional groups in production water from five petroleum reservoirs in China were investigated by chemical and molecular biological analyses. The dominant and core phyla in the five oil reservoirs were Proteobacteria, Deferribacterota, Firmicutes, Desulfobacterota, Euryarchaeota and Thermoplasmatota.

Discovery of the non-cosmopolitan lineages in Candidatus Thermoprofundales.

The recently proposed order Candidatus Thermoprofundales, currently containing only one family-level lineage Marine Benthic Group-D (MBG-D), is distributed in global subsurface ecosystems and ecologically important, but its diversity, evolution and metabolism remain largely unknown. Here we described two novel family-level specialized lineages in Ca. Thermoprofundales, JdFR-43 and HyVt, which are restricted to specific biotopes (primarily in marine hydrothermal vents and occasionally in oil reservoirs and hot springs) in contrast to the cosmopolitan lineage MBG-D.

Microbial Lipopeptide-Producing Strains and Their Metabolic Roles under Anaerobic Conditions.

The lipopeptide produced by microorganisms is one of the representative biosurfactants and is characterized as a series of structural analogues of different families. Thirty-four families covering about 300 lipopeptide compounds have been reported in the last decades, and most of the reported lipopeptides produced by microorganisms were under aerobic conditions. The lipopeptide-producing strains under anaerobic conditions have attracted much attention from both the academic and industrial communities, due to the needs and the challenge of their applications in anaerobic environments, such as in oil reservoirs and in microbial enhanced oil recovery (MEOR).

New evidence for a hydroxylation pathway for anaerobic alkane degradation supported by analyses of functional genes and signature metabolites in oil reservoirs.

Microbial degradation of recalcitrant alkanes under anaerobic conditions results in the accumulation of heavy oil fraction in oil reservoirs. Hydroxylation of alkanes is an important activation mechanism under anaerobic conditions, but the diversity and distribution of the responsible microorganisms in the subsurface environment are still unclear. The lack of functional gene polymerase chain reaction (PCR) primers and commercially available intermediate degradation chemical compounds are the major obstacles for this research.

The optimization of heterogeneous catalytic conditions in the direct alkylation of waste vegetable oil.

Alkylated waste vegetable oil is a versatile intermediate product in the synthesis of bio-based materials. Heterogeneous catalytic condition with high conversion rate in the direct alkylation of waste vegetable oil was reported and the deactivation mechanism of catalyst was revealed. The total exchange capacity, elemental composition and pyrolysis product of catalyst before and after the alkylation reaction were analysed by back titration, elemental analysis, electrospray ionization mass spectrometry, gas chromatography mass spectrometry and pyrolysis-gas chromatography/mass spectrometry, respectively.

Anaerobic Degradation of Paraffins by Thermophilic Actinobacteria under Methanogenic Conditions.

Microbial anaerobic alkane degradation is a key process in subsurface oil reservoirs and anoxic environments contaminated with petroleum, with a major impact on global carbon cycling. However, the thermophiles capable of water-insoluble paraffins (>C) degradation under methanogenic conditions has remained understudied. Here, we established thermophilic (55 °C) -paraffins-degrading (C-C) cultures from an oil reservoir.

Simultaneous detection of transcribed functional assA gene and the corresponding metabolites of linear alkanes (C, C, and C) in production water of a low-temperature oil reservoir.

Methanogenic hydrocarbon degradation is an important biogeochemical process in oil reservoirs; however, genomic DNA-based analysis of microorganisms and metabolite detection are not conclusive for identification of the ongoing nature of this bioprocess. In this study, a suite of analyses, involving the study of microbial community and selective gene quantification of both genomic DNA and RNA together with signature metabolites, were performed to comprehensively advance the understanding of the methanogenic biodegradation of hydrocarbons in a low-temperature oilfield. The fumarate addition products for alkanes-C, C, and C-alkylsuccinates-and transcribed assA and mcrA genes were simultaneously detected in the production water sample, providing robust and convincing evidence for both the initial activation of n-alkanes and methane metabolism in this oilfield.

Synthesis and mass spectra of rearrangement bio-signature metabolites of anaerobic alkane degradation via fumarate addition.

Metabolite profiling in anaerobic alkane biodegradation plays an important role in revealing activation mechanisms. Apart from alkylsuccinates, which are considered to be the usual biomarkers via fumarate addition, the downstream metabolites of C-skeleton rearrangement can also be regarded as biomarkers. However, it is difficult to detect intermediate metabolites in both environmental samples and enrichment cultures, resulting in lacking direct evidence to prove the occurrence of fumarate addition pathway.

Long-chain n-alkane biodegradation coupling to methane production in an enriched culture from production water of a high-temperature oil reservoir.

Paraffinic n-alkanes (C22-C30), crucial portions of residual oil, are generally considered to be difficult to be biodegraded owing to their general solidity at ambient temperatures and low water solubility, rendering relatively little known about metabolic processes in different methanogenic hydrocarbon-contaminated environments. Here, we established a methanogenic C22-C30 n-alkane-degrading enrichment culture derived from a high-temperature oil reservoir production water. During two-year incubation (736 days), unexpectedly significant methane production was observed.

Methanogenic biodegradation of C to Cn-alkanes initiated by Smithella via fumarate addition mechanism.

In the present study, a methanogenic alkane-degrading (a mixture of C to Cn-alkanes) culture enriched from production water of a low-temperature oil reservoir was established and assessed. Significant methane production was detected in the alkane-amended enrichment cultures compared with alkane-free controls over an incubation period of 1 year. At the end of the incubation, fumarate addition metabolites (C to C alkylsuccinates) and assA genes (encoding the alpha subunit of alkylsuccinate synthase) were detected only in the alkane-amended enrichment cultures.

Methanogenic Degradation of Long -Alkanes Requires Fumarate-Dependent Activation.

Methanogenic degradation of -alkanes is prevalent in -alkane-impacted anoxic oil reservoirs and oil-polluted sites. However, little is known about the initial activation mechanism of the substrate, especially -alkanes with a chain length above C Here, a methanogenic C to C-alkane-degrading enrichment culture was established from production water of a low-temperature oil reservoir. At the end of the incubation (364 days), C to C (1-methylalkyl)succinates were detected in the -alkane-amended enrichment culture, suggesting that fumarate addition had occurred in the degradation process.

Anaerobic hydrocarbon degradation in candidate phylum 'Atribacteria' (JS1) inferred from genomics.

The hydrocarbon-enriched environments, such as oil reservoirs and oil sands tailings ponds, contain a broad diversity of uncultured microorganisms. Despite being one of the few prokaryotic lineages that is consistently detected in both production water from oil reservoirs and stable hydrocarbon-degrading enrichment cultures originated from oil reservoirs, the physiological and ecological roles of candidate phylum "Atribacteria" (OP9/JS1) are not known in deep subsurface environments. Here, we report the expanded metabolic capabilities of Atribacteria as inferred from genomic reconstructions.

Direct microbial transformation of carbon dioxide to value-added chemicals: A comprehensive analysis and application potentials.

Carbon dioxide storage in petroleum and other geological reservoirs is an economical option for long-term separation of this gas from the atmosphere. Other options include applications through conversion to valuable chemicals. Microalgae and plants perform direct fixation of carbon dioxide to biomass, which is then used as raw material for further microbial transformation (MT).