In order to implement industrial production of selected functional bacteria for bioremediation of shrimp culture environment, the fermentation conditions of the three functional bacteria, which have high ability in de...In order to implement industrial production of selected functional bacteria for bioremediation of shrimp culture environment, the fermentation conditions of the three functional bacteria, which have high ability in degrading organic pollutants at the bottom of shrimp ponds, were studied. The results showed that the favorable fermentation medium （per L） was 25 g of peptone, 5 g of yeast extract, and 0.2 g of ferric phosphate, and the initial pH value of the medium was 8.0. The optimum fermentation time was 20 h. The optimum stirring way was stirring one hour after one hour. Iso-electric point sedimentation collecting method was the most efficient and economic method to collect the bacteria cells after fermentation, with the optimum sediment pH of 3.67, 4.02, and 3.40 for the strains Lt7222, Gy7018 and Lt7511,respectively. It was also indicated that the survival and reproducing ability of the bacterial cells were not affected by the sedimentation process.展开更多
Objective: To study the effect of surface configuration on the corrosion resistance and bacterium accumulation of pure Titanium(Ti) when used in oral environment. Methods: Six edentulous volunteers with healthy oral m...Objective: To study the effect of surface configuration on the corrosion resistance and bacterium accumulation of pure Titanium(Ti) when used in oral environment. Methods: Six edentulous volunteers with healthy oral mucosa participated in an in vivo study. Two kinds of pure Ti testing pieces with plane and wrinkly surface were fixed in the polished surface of upper complete dentures. After 6-month wearing, dynamic polarization curves were traced with electrochemical method and the amount and species of bacterium adhered on pure Ti were examined. Results: ① Ep and Ip of specimen in oral cavity was higher than that left in air, which meant corrosion resistance falling. Compared to plane one, Ecorr of wrinkly specimen was more positive and Ep and Ip were more higher, so its corrosion resistance reduced. ② Individual difference put a significant influence on amount of bacterium adhered on pure Titanium, but had no relation to species of bacterium. To the same patient, wrinkly samples collected more bacterium than plane ones, and exhibited G - coccus beside G + coccus. Conclusion: From the perspective of corrosion behavior and benefit to periodontal tissue, wrinkly surface should not be adopted when pure Ti prosthesis is made,especially on connector part of denture.展开更多
Metal contamination in the environment is a global concern due to its high toxicity to living organisms and its worldwide distribution. The principal goal of this review is to examine the current strategies and techno...Metal contamination in the environment is a global concern due to its high toxicity to living organisms and its worldwide distribution. The principal goal of this review is to examine the current strategies and technologies for the remediation of metal- contaminated soils by metal-accumulating plants and assess the roles of arbnscular mycorrhizal （AM） fungi in remediation of soils under hyperaccumulator or non-accumulator plants. The use of plants to remove metals from the environment or reduce the toxicity, known as phytoremediation, is an environmentally sustainable and low cost remediation technology. The mechanisms of the use of hyperaccumulator plants for phytoremediation included solubilization of the metal in the soil matrix, the plant uptake of the metal, detoxification/chelation and sequestration, and volatilization. Recently, some ecologists have found that phytoremediation with the aids of mycorrhizae can enhance efficiency in the removal of toxic metals. AM fungi can facilitate the survival of their host plants growing on metal-contaminated land by enhancing their nutrient acquisition, protecting them from the metal toxicity, absorbing metals, and also enhancing phytostabilization and phytoextraction. Such information may be useful for developing phytoremediation program at metal-contaminated sites.展开更多
文摘In order to implement industrial production of selected functional bacteria for bioremediation of shrimp culture environment, the fermentation conditions of the three functional bacteria, which have high ability in degrading organic pollutants at the bottom of shrimp ponds, were studied. The results showed that the favorable fermentation medium （per L） was 25 g of peptone, 5 g of yeast extract, and 0.2 g of ferric phosphate, and the initial pH value of the medium was 8.0. The optimum fermentation time was 20 h. The optimum stirring way was stirring one hour after one hour. Iso-electric point sedimentation collecting method was the most efficient and economic method to collect the bacteria cells after fermentation, with the optimum sediment pH of 3.67, 4.02, and 3.40 for the strains Lt7222, Gy7018 and Lt7511,respectively. It was also indicated that the survival and reproducing ability of the bacterial cells were not affected by the sedimentation process.
文摘Objective: To study the effect of surface configuration on the corrosion resistance and bacterium accumulation of pure Titanium(Ti) when used in oral environment. Methods: Six edentulous volunteers with healthy oral mucosa participated in an in vivo study. Two kinds of pure Ti testing pieces with plane and wrinkly surface were fixed in the polished surface of upper complete dentures. After 6-month wearing, dynamic polarization curves were traced with electrochemical method and the amount and species of bacterium adhered on pure Ti were examined. Results: ① Ep and Ip of specimen in oral cavity was higher than that left in air, which meant corrosion resistance falling. Compared to plane one, Ecorr of wrinkly specimen was more positive and Ep and Ip were more higher, so its corrosion resistance reduced. ② Individual difference put a significant influence on amount of bacterium adhered on pure Titanium, but had no relation to species of bacterium. To the same patient, wrinkly samples collected more bacterium than plane ones, and exhibited G - coccus beside G + coccus. Conclusion: From the perspective of corrosion behavior and benefit to periodontal tissue, wrinkly surface should not be adopted when pure Ti prosthesis is made,especially on connector part of denture.
基金Supported by the Research Grant Council,Hong Kong SAR,China
文摘Metal contamination in the environment is a global concern due to its high toxicity to living organisms and its worldwide distribution. The principal goal of this review is to examine the current strategies and technologies for the remediation of metal- contaminated soils by metal-accumulating plants and assess the roles of arbnscular mycorrhizal （AM） fungi in remediation of soils under hyperaccumulator or non-accumulator plants. The use of plants to remove metals from the environment or reduce the toxicity, known as phytoremediation, is an environmentally sustainable and low cost remediation technology. The mechanisms of the use of hyperaccumulator plants for phytoremediation included solubilization of the metal in the soil matrix, the plant uptake of the metal, detoxification/chelation and sequestration, and volatilization. Recently, some ecologists have found that phytoremediation with the aids of mycorrhizae can enhance efficiency in the removal of toxic metals. AM fungi can facilitate the survival of their host plants growing on metal-contaminated land by enhancing their nutrient acquisition, protecting them from the metal toxicity, absorbing metals, and also enhancing phytostabilization and phytoextraction. Such information may be useful for developing phytoremediation program at metal-contaminated sites.
