Bacterial suspension is an essential component of microbially induced carbonate precipitation(MICP)-based biocement and a large-scale production is required for field applications.In this study,a new bacterial concent...Bacterial suspension is an essential component of microbially induced carbonate precipitation(MICP)-based biocement and a large-scale production is required for field applications.In this study,a new bacterial concentration method is proposed to enable high concentration bacterial suspension to be produced to facilitate field work.By adding low concentration calcium to bacterial suspension,flocs are formed and bacterial cells are adsorbed on the flocs to achieve bacterial concentration.Compared to the traditional bacterial concentration method using centrifugation and freezing-drying method,the proposed method can concentrate a large volume of bacterial suspension without using special equipment.The feasibility of this method is verified by bacterial concentration tests,solution tests and sand column treatment tests.The results of both the solution test and the sand column treatment test show that the bacterial suspension concentrated by the proposed method can be effectively used for soil biocementation.There is a threshold calcium concentration that allows a complete bacterial concentration for the proposed method,and this threshold calcium concentration tends to increase linearly with the optical density of the cell suspension at a wavelength of 600 nm(OD_(600)).展开更多
Nipah （Nypafruticans） is a species of palm trees that grows in mangroves environment near the sea shore. Nipah is potential to produce biofuel energy. The purposes of this research were 1） to determine the optimum ...Nipah （Nypafruticans） is a species of palm trees that grows in mangroves environment near the sea shore. Nipah is potential to produce biofuel energy. The purposes of this research were 1） to determine the optimum bacterial concentration for fermentation to produce high concentration of bio-ethanol, and 2） to determine the optimum incubation time for fermentation to produce high concentration of bio-ethanol. The research had been conducted from June until November 2009 using nipah sap as the substrate and Saceharomyces cerevisiae as a fermentation starter. The experimental design used was a randomized block design （RBD）. Factors tested were starter concentration （5%, 7.5%, 10%） and incubation time （2, 4, 6 days）. The variables observed were concentration of reducing sugar, total microorganism （CFU/mL）, and bio-ethanol production. The results showed that the highest yield of bio-ethanol （8.98%） was produced with 7.5% of starter concentration and 6 days of incubation time.展开更多
Microbial enhanced oil recovery (MEOR) is the research focus in the field of energy development as an environmentally friendly and low cost technology. MEOR can bes divided into indigenous microbial oil recovery and e...Microbial enhanced oil recovery (MEOR) is the research focus in the field of energy development as an environmentally friendly and low cost technology. MEOR can bes divided into indigenous microbial oil recovery and exogenous microbial oil recovery. The ultimate goal of indigenous microbial flooding is to enhance oil recovery via stimulation of specific indigenous microorganisms by injecting optimal nutrients. For studying the specific rule to activate the indigenous community during the long-term injection period, a series of indigenous displacement flooding experiments were carried out by using the long-core physical simulation test. The experimental results have shown that the movement of nutrients components (i.e., carbon/nitrogen/phosphorus) differed from the consumption of them. Moreover, there was a positive relationship between the nutrients concentration and bacteria concentration once observed in the produced fluid. And the trend of concentration of acetic acid was consistent with that of methanogens. When adding same activators, the impacts of selective activators to stimulate the indigenous microorganisms became worse along with the injection period, which led to less oil recovery efficiency.展开更多
The ability of particles to stabilize liquid films has broad applications in many fields,such as drug delivery,biofuel catalysis,and crude-oil separation.The mechanism of particles to stabilize emulsions has been wide...The ability of particles to stabilize liquid films has broad applications in many fields,such as drug delivery,biofuel catalysis,and crude-oil separation.The mechanism of particles to stabilize emulsions has been widely studied.However,how particles affect the stability of suspension films is still unclear.Here,the dynamics of bacterial particles on free liquid films during evaporation is obtained by direct microscopic observation.We find that the initial concentration of the bacterial solution affects the evolution of the shapes and stabilities of liquid films.The liquid film with a low bacterial concentration exhibits a drainage and rupture process similar to pure water,and bacteria would be evacuated during the evaporation of liquid film.However,when the bacterial concentration is high,bacteria form a single-layer array in the center of the film and greatly enhance the stability of the liquid film.We demonstrate that these two distinct film evaporation dynamics are caused by the difference in the lateral capillary force of the particles at different positions on the liquid film,which is not affected by the active motility of particle.Together,our research reveals the critical role of bacteria concentration in stabilizing suspension liquid film.展开更多
基金supports by the National Natural Science Foundation of China(Grant Nos.52108307 and 52178319)the National Natural Science Foundation of Fujian Province,China(Grant No.2022J05020).
文摘Bacterial suspension is an essential component of microbially induced carbonate precipitation(MICP)-based biocement and a large-scale production is required for field applications.In this study,a new bacterial concentration method is proposed to enable high concentration bacterial suspension to be produced to facilitate field work.By adding low concentration calcium to bacterial suspension,flocs are formed and bacterial cells are adsorbed on the flocs to achieve bacterial concentration.Compared to the traditional bacterial concentration method using centrifugation and freezing-drying method,the proposed method can concentrate a large volume of bacterial suspension without using special equipment.The feasibility of this method is verified by bacterial concentration tests,solution tests and sand column treatment tests.The results of both the solution test and the sand column treatment test show that the bacterial suspension concentrated by the proposed method can be effectively used for soil biocementation.There is a threshold calcium concentration that allows a complete bacterial concentration for the proposed method,and this threshold calcium concentration tends to increase linearly with the optical density of the cell suspension at a wavelength of 600 nm(OD_(600)).
文摘Nipah （Nypafruticans） is a species of palm trees that grows in mangroves environment near the sea shore. Nipah is potential to produce biofuel energy. The purposes of this research were 1） to determine the optimum bacterial concentration for fermentation to produce high concentration of bio-ethanol, and 2） to determine the optimum incubation time for fermentation to produce high concentration of bio-ethanol. The research had been conducted from June until November 2009 using nipah sap as the substrate and Saceharomyces cerevisiae as a fermentation starter. The experimental design used was a randomized block design （RBD）. Factors tested were starter concentration （5%, 7.5%, 10%） and incubation time （2, 4, 6 days）. The variables observed were concentration of reducing sugar, total microorganism （CFU/mL）, and bio-ethanol production. The results showed that the highest yield of bio-ethanol （8.98%） was produced with 7.5% of starter concentration and 6 days of incubation time.
文摘Microbial enhanced oil recovery (MEOR) is the research focus in the field of energy development as an environmentally friendly and low cost technology. MEOR can bes divided into indigenous microbial oil recovery and exogenous microbial oil recovery. The ultimate goal of indigenous microbial flooding is to enhance oil recovery via stimulation of specific indigenous microorganisms by injecting optimal nutrients. For studying the specific rule to activate the indigenous community during the long-term injection period, a series of indigenous displacement flooding experiments were carried out by using the long-core physical simulation test. The experimental results have shown that the movement of nutrients components (i.e., carbon/nitrogen/phosphorus) differed from the consumption of them. Moreover, there was a positive relationship between the nutrients concentration and bacteria concentration once observed in the produced fluid. And the trend of concentration of acetic acid was consistent with that of methanogens. When adding same activators, the impacts of selective activators to stimulate the indigenous microorganisms became worse along with the injection period, which led to less oil recovery efficiency.
基金supported by the National Natural Science Foundation of China(Grants 11872357,11622222,and 12002338)the Fundamental Research Funds for the Central Universities,the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant XDB22040403)+4 种基金the Thousand Young Talents Program of China,the National Postdoctoral Program for Innovative Talents(Grant BX20190318)the China Postdoctoral Science Foundation(Grant 2019M662188)the Fundamental Research Funds for the Central Universities(Grant WK2090000017)the USTC Research Funds of the Double First-Class Initiative(Grant YD2480002001)the Anhui Provincial Natural Science Foundation(Grant 2008085QA24).
文摘The ability of particles to stabilize liquid films has broad applications in many fields,such as drug delivery,biofuel catalysis,and crude-oil separation.The mechanism of particles to stabilize emulsions has been widely studied.However,how particles affect the stability of suspension films is still unclear.Here,the dynamics of bacterial particles on free liquid films during evaporation is obtained by direct microscopic observation.We find that the initial concentration of the bacterial solution affects the evolution of the shapes and stabilities of liquid films.The liquid film with a low bacterial concentration exhibits a drainage and rupture process similar to pure water,and bacteria would be evacuated during the evaporation of liquid film.However,when the bacterial concentration is high,bacteria form a single-layer array in the center of the film and greatly enhance the stability of the liquid film.We demonstrate that these two distinct film evaporation dynamics are caused by the difference in the lateral capillary force of the particles at different positions on the liquid film,which is not affected by the active motility of particle.Together,our research reveals the critical role of bacteria concentration in stabilizing suspension liquid film.
