A Bacillus subtilis strain JA-1 isolated from an oil reservoir was studied. This strain is capable of growth and producing biosurfactant at a temperature of 60 ℃. In nutrient medium it produced biosurfactant which re...A Bacillus subtilis strain JA-1 isolated from an oil reservoir was studied. This strain is capable of growth and producing biosurfactant at a temperature of 60 ℃. In nutrient medium it produced biosurfactant which reduced the surface tension from 68.2 mN/m to 28.3 mN/m, with the critical micelle concentration （CMC） of 48 mg/L. The measured surface tension indicated that the biosurfactant possessed stable surface activity at high temperature and a specific range of pH and salt concentrations. The results of thin layer chromatography （TLC） together with FT-IR showed that the metabolic product of strain JA-1 is a lipopeptide biosurfactant. The ability to growth at high temperature and to produce biosurfactant makes strain JA-1 promising for enhanced oil recovery.展开更多
Infection and intoxication are two common types of foodborne illnesses throughout the world.The aim of the present work was to isolate and characterize biosurfactant producing bacteria fromgroundnut oil cake dumping s...Infection and intoxication are two common types of foodborne illnesses throughout the world.The aim of the present work was to isolate and characterize biosurfactant producing bacteria fromgroundnut oil cake dumping sites and evaluate their biocontrol effects against foodborne pathogens.Bacteria were isolated by enrichment culture technique and preliminary screening method.Biosurfactant activity evaluation was carried out by oil displacement,drop collapse test,lipase activity,hemolytic activity,emulsification index and emulsification assay methods.16s rRNA sequence analysis was used for the isolate identification.Crude biosurfactant was extracted by acid precipitation method and characterized using FTIR(Fourier Transform Infrared Spectroscopy).Antibacterial activity was investigated using disc diffusion method.CMCand surface reduction were analyzed by DuNouy tensiometer.Top 10 strains were selected for biosurfactant activity assessment from the total 30 isolates.In addition,16s rRNA sequence identified that the potential isolate was Bacillus pseudomycoides OR 1.Then,FTIR result of the extracted biosurfactant established the extract as a lipopeptide based on the absorption peaks at 3500 to 3200 cm^-1 and 2963 to 2854.68 cm^-1,respectively.50μg/mL of lipopeptide showed the highest antibacterial activity.Critical Micelle Concentration(CMC)of the lipopeptide was 60 mg/L and it reduced the surface tension of water from 71.6 to 31.6 mN/m.Hence,this study widens the scope to employ the bacterial lipopeptide surfactant as a promising biocontrol agent against foodborne pathogens.展开更多
This paper introduces the results of selecting and breeding a micro-organism, Strain I, and its core model experiment investigation for microbial enhanced oil recovery (MEOR). Strain I was separated from the formation...This paper introduces the results of selecting and breeding a micro-organism, Strain I, and its core model experiment investigation for microbial enhanced oil recovery (MEOR). Strain I was separated from the formation water of the Dagang oil field, with analytical results showing that Strain I is a gram-positive bacillus. A further study revealed that this strain has an excellent tolerance of environmental stresses: It can survive in conditions of 70℃, 30 wt% salinity and pH3.5-9.4. Strain I can metabolize biosurfactants that could increase the oil recovery ratio, use crude oil as the single carbon source, and decompose long-chain paraffin with a large molecular weight into short-chain paraffin with a small molecular weight. The core model experiment shows that Strain I enhances oil recovery well. Using 2 vol% of the fermentation solution of Strain I to displace the crude oil in the synthetic plastic bonding core could increase the recovery ratio by 21.6%.展开更多
Foodborne pathogen poses a threat to the food industries as many outbreaks have been found to be associated with biofilm formation.The formation of biofilm is a self-protection growth pattern of bacteria,which increas...Foodborne pathogen poses a threat to the food industries as many outbreaks have been found to be associated with biofilm formation.The formation of biofilm is a self-protection growth pattern of bacteria,which increases post-processing contamination and risk to public health.It is difficult to eliminate the biofilm in the food industries,since the biofilm cells have a barrier preventing or lessening the contact with environmental stresses,antimicrobial agents and the host immune system.Bacterial biofilm formation is a complex process,including initial attachment stage,irreversible attachment stage,biofilm development stage,biofilm maturation stage,and biofilm dispersion stage.The genetic mechanism,substratum and bacterial cell surface properties involve in the biofilm formation.The biofilm inhibition methods studied are physical treatment,chemical and biochemical treatment.The potential green and safe biochemical method attracts more attention,especially,the novel strategies using the safe biochemical agents(essential oils,enzymes,biosurfactants,others)constantly emerged.The review emphasized on effective strategies for inhibiting biofilm formation in different stages(initial irreversible attachment,formation,and maturation)by use of biochemical agents,aiming to provide new insight into biofilm control in food industry thus improving food quality and safety.展开更多
基金supported by the National High-technology Research and Development Program(863Program)of China(Grant No.2009AA063504)China National Petroleum Corporation Science&Technology Management Program(2008A-1403)
文摘A Bacillus subtilis strain JA-1 isolated from an oil reservoir was studied. This strain is capable of growth and producing biosurfactant at a temperature of 60 ℃. In nutrient medium it produced biosurfactant which reduced the surface tension from 68.2 mN/m to 28.3 mN/m, with the critical micelle concentration （CMC） of 48 mg/L. The measured surface tension indicated that the biosurfactant possessed stable surface activity at high temperature and a specific range of pH and salt concentrations. The results of thin layer chromatography （TLC） together with FT-IR showed that the metabolic product of strain JA-1 is a lipopeptide biosurfactant. The ability to growth at high temperature and to produce biosurfactant makes strain JA-1 promising for enhanced oil recovery.
文摘Infection and intoxication are two common types of foodborne illnesses throughout the world.The aim of the present work was to isolate and characterize biosurfactant producing bacteria fromgroundnut oil cake dumping sites and evaluate their biocontrol effects against foodborne pathogens.Bacteria were isolated by enrichment culture technique and preliminary screening method.Biosurfactant activity evaluation was carried out by oil displacement,drop collapse test,lipase activity,hemolytic activity,emulsification index and emulsification assay methods.16s rRNA sequence analysis was used for the isolate identification.Crude biosurfactant was extracted by acid precipitation method and characterized using FTIR(Fourier Transform Infrared Spectroscopy).Antibacterial activity was investigated using disc diffusion method.CMCand surface reduction were analyzed by DuNouy tensiometer.Top 10 strains were selected for biosurfactant activity assessment from the total 30 isolates.In addition,16s rRNA sequence identified that the potential isolate was Bacillus pseudomycoides OR 1.Then,FTIR result of the extracted biosurfactant established the extract as a lipopeptide based on the absorption peaks at 3500 to 3200 cm^-1 and 2963 to 2854.68 cm^-1,respectively.50μg/mL of lipopeptide showed the highest antibacterial activity.Critical Micelle Concentration(CMC)of the lipopeptide was 60 mg/L and it reduced the surface tension of water from 71.6 to 31.6 mN/m.Hence,this study widens the scope to employ the bacterial lipopeptide surfactant as a promising biocontrol agent against foodborne pathogens.
文摘This paper introduces the results of selecting and breeding a micro-organism, Strain I, and its core model experiment investigation for microbial enhanced oil recovery (MEOR). Strain I was separated from the formation water of the Dagang oil field, with analytical results showing that Strain I is a gram-positive bacillus. A further study revealed that this strain has an excellent tolerance of environmental stresses: It can survive in conditions of 70℃, 30 wt% salinity and pH3.5-9.4. Strain I can metabolize biosurfactants that could increase the oil recovery ratio, use crude oil as the single carbon source, and decompose long-chain paraffin with a large molecular weight into short-chain paraffin with a small molecular weight. The core model experiment shows that Strain I enhances oil recovery well. Using 2 vol% of the fermentation solution of Strain I to displace the crude oil in the synthetic plastic bonding core could increase the recovery ratio by 21.6%.
基金the Science and Technology Project of Henan Province(212102110320)the Science Foundation of Henan University of Technology(Grant Nos.2020BS013,2019BS029)
文摘Foodborne pathogen poses a threat to the food industries as many outbreaks have been found to be associated with biofilm formation.The formation of biofilm is a self-protection growth pattern of bacteria,which increases post-processing contamination and risk to public health.It is difficult to eliminate the biofilm in the food industries,since the biofilm cells have a barrier preventing or lessening the contact with environmental stresses,antimicrobial agents and the host immune system.Bacterial biofilm formation is a complex process,including initial attachment stage,irreversible attachment stage,biofilm development stage,biofilm maturation stage,and biofilm dispersion stage.The genetic mechanism,substratum and bacterial cell surface properties involve in the biofilm formation.The biofilm inhibition methods studied are physical treatment,chemical and biochemical treatment.The potential green and safe biochemical method attracts more attention,especially,the novel strategies using the safe biochemical agents(essential oils,enzymes,biosurfactants,others)constantly emerged.The review emphasized on effective strategies for inhibiting biofilm formation in different stages(initial irreversible attachment,formation,and maturation)by use of biochemical agents,aiming to provide new insight into biofilm control in food industry thus improving food quality and safety.
