Afifella marina strain ME (KC205142), a purple non-sulfur bacterium was isolated from mangrove habitats of Sabah. The effects of light intensities and photoperiods on proteolytic activity in Afifella marina strain ME ...Afifella marina strain ME (KC205142), a purple non-sulfur bacterium was isolated from mangrove habitats of Sabah. The effects of light intensities and photoperiods on proteolytic activity in Afifella marina strain ME (KC205142) were investigated. Secretion of proteolytic enzymes in Afifella marina was preliminarily assessed by skim milk agarose media. Subsequently, light intensities, such as, dark, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500 and 5000 lux were used to evaluate the effects on proteolytic activity in Afifella marina strain ME under anaerobic condition. After that, the effect of photoperiods on proteolytic activity was monitored under anaerobic light condition (3000 lux) at 0 h (0L/24D), 6 h (6L/18D), 12 h (12L/12D), 18 h (18L/6D) and 24 h (24L/0D) of photoperiod. The highest proteolytic activity of 74.67 U was recorded at 3000 lux illumination light intensity. The proteolytic activity in bacterium Afifella marina strain ME was positively associated with the dry cell weight. The proteolytic activity of 72.67 U in bacterium Afifella marina strain ME at 18 h (18L/6D) photoperiod is not significantly different (p > 0.05) from proteolytic activity of 74.67 U recorded at continuous light (24L/0D) condition. Light intensity of 3000 lux, culture period of 48 h and a photoperiod of 18 h (18L/ 6D) were the optimum parameters for proteolytic activity in bacterium Afifella marina strain ME.展开更多
Sustainable use of palm oil mill effluent (POME) has been the major focus in the recent development in palm oil industry due to the fact that environmental issue brought by POME. The purpose of this study was to deter...Sustainable use of palm oil mill effluent (POME) has been the major focus in the recent development in palm oil industry due to the fact that environmental issue brought by POME. The purpose of this study was to determine the optimum incubation period of purple non-sulphur bacterium (PNSB) in reduction of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) in settled POME and to determine the dry cell weight, TN, TP and cell yield of PNSB. Pure isolate of Rhodobacter sphaeroides strain UMSFW1 was cultured in settled POME under anaerobic condition at 2500 lux illumination on light intensity at a temperature of 30°C ± 2°C for 144-h. Parameters such as COD (mg/L), dry cell biomass (g/L), TP (mg/L) and TN (mg/L) in settled POME and bacterial cells were analyzed. A total reduction of TN (43.9%) in settled POME and a total increase of TN (43.2%) in bacterial cell were recorded at the end of experiment. At the same time the reduction of 51.5% chemical oxygen demand was determined from the POME. The highest dry cell weight of 2.44 g/L with cell yield 0.39 (mg/cell/mg COD) was achieved at the end of experiment. A total 24.7% of TP reduction in settled POME was achieved in 144-h culture, but while a maximum 10% of TP in bacterial cell was achieved in 48-h culture. This study shows that PNSB Rhodobacter sphaeroides strain UMSFW1 grows well by using settled POME as substrate and is capable to remove TN in the settled POME and assimilate into bacterial biomass. This study could provide us a further insight in the nutrient removal and COD removal in the bioremediation process by bacterium Rhodobacter sphaeroides strain UMSFW1.展开更多
Soybean wastewater was used to generate biomass resource by use of purple non-sulfur bacteria（PNSB）. This study investigated the enhancement of PNSB cell accumulation in wastewater by Mg2＋under the light-anaerobic ...Soybean wastewater was used to generate biomass resource by use of purple non-sulfur bacteria（PNSB）. This study investigated the enhancement of PNSB cell accumulation in wastewater by Mg2＋under the light-anaerobic condition. Results showed that with the optimal Mg2＋dosage of 10 mg/L, biomass production was improved by 70% to 3630 mg/L,and biomass yield also was improved by 60%. Chemical Oxygen Demand（COD） removal reached above 86% and hydraulic retention time was shortened from 96 to 72 hr. The mechanism analysis indicated that Mg2＋could promote the content of bacteriochlorophyll in photosynthesis because Mg2＋is the bacteriochlorophyll active center, and thus improved adenosine triphosphate（ATP） production. An increase of ATP production enhanced the conversion of organic matter in wastewater into PNSB cell materials（biomass yield） and COD removal, leading to more biomass production. With 10 mg/L Mg2＋, bacteriochlorophyll content and ATP production were improved by 60% and 33% respectively.展开更多
文摘Afifella marina strain ME (KC205142), a purple non-sulfur bacterium was isolated from mangrove habitats of Sabah. The effects of light intensities and photoperiods on proteolytic activity in Afifella marina strain ME (KC205142) were investigated. Secretion of proteolytic enzymes in Afifella marina was preliminarily assessed by skim milk agarose media. Subsequently, light intensities, such as, dark, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500 and 5000 lux were used to evaluate the effects on proteolytic activity in Afifella marina strain ME under anaerobic condition. After that, the effect of photoperiods on proteolytic activity was monitored under anaerobic light condition (3000 lux) at 0 h (0L/24D), 6 h (6L/18D), 12 h (12L/12D), 18 h (18L/6D) and 24 h (24L/0D) of photoperiod. The highest proteolytic activity of 74.67 U was recorded at 3000 lux illumination light intensity. The proteolytic activity in bacterium Afifella marina strain ME was positively associated with the dry cell weight. The proteolytic activity of 72.67 U in bacterium Afifella marina strain ME at 18 h (18L/6D) photoperiod is not significantly different (p > 0.05) from proteolytic activity of 74.67 U recorded at continuous light (24L/0D) condition. Light intensity of 3000 lux, culture period of 48 h and a photoperiod of 18 h (18L/ 6D) were the optimum parameters for proteolytic activity in bacterium Afifella marina strain ME.
文摘Sustainable use of palm oil mill effluent (POME) has been the major focus in the recent development in palm oil industry due to the fact that environmental issue brought by POME. The purpose of this study was to determine the optimum incubation period of purple non-sulphur bacterium (PNSB) in reduction of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) in settled POME and to determine the dry cell weight, TN, TP and cell yield of PNSB. Pure isolate of Rhodobacter sphaeroides strain UMSFW1 was cultured in settled POME under anaerobic condition at 2500 lux illumination on light intensity at a temperature of 30°C ± 2°C for 144-h. Parameters such as COD (mg/L), dry cell biomass (g/L), TP (mg/L) and TN (mg/L) in settled POME and bacterial cells were analyzed. A total reduction of TN (43.9%) in settled POME and a total increase of TN (43.2%) in bacterial cell were recorded at the end of experiment. At the same time the reduction of 51.5% chemical oxygen demand was determined from the POME. The highest dry cell weight of 2.44 g/L with cell yield 0.39 (mg/cell/mg COD) was achieved at the end of experiment. A total 24.7% of TP reduction in settled POME was achieved in 144-h culture, but while a maximum 10% of TP in bacterial cell was achieved in 48-h culture. This study shows that PNSB Rhodobacter sphaeroides strain UMSFW1 grows well by using settled POME as substrate and is capable to remove TN in the settled POME and assimilate into bacterial biomass. This study could provide us a further insight in the nutrient removal and COD removal in the bioremediation process by bacterium Rhodobacter sphaeroides strain UMSFW1.
基金supported by the National Natural Science Foundation of China(No.51278489)
文摘Soybean wastewater was used to generate biomass resource by use of purple non-sulfur bacteria（PNSB）. This study investigated the enhancement of PNSB cell accumulation in wastewater by Mg2＋under the light-anaerobic condition. Results showed that with the optimal Mg2＋dosage of 10 mg/L, biomass production was improved by 70% to 3630 mg/L,and biomass yield also was improved by 60%. Chemical Oxygen Demand（COD） removal reached above 86% and hydraulic retention time was shortened from 96 to 72 hr. The mechanism analysis indicated that Mg2＋could promote the content of bacteriochlorophyll in photosynthesis because Mg2＋is the bacteriochlorophyll active center, and thus improved adenosine triphosphate（ATP） production. An increase of ATP production enhanced the conversion of organic matter in wastewater into PNSB cell materials（biomass yield） and COD removal, leading to more biomass production. With 10 mg/L Mg2＋, bacteriochlorophyll content and ATP production were improved by 60% and 33% respectively.
