Biodesulfurization （BDS） is a promising technology for deep desulfurization. In this work, Pseudomonas delafieldii R-8 cells are immobilized in calcium alginate beads and used for BDS of transportation fuels. It is ...Biodesulfurization （BDS） is a promising technology for deep desulfurization. In this work, Pseudomonas delafieldii R-8 cells are immobilized in calcium alginate beads and used for BDS of transportation fuels. It is found that thiophene and dibenzothiophene （DBT） can be simultaneously metabolized by immobilized R-8 cells. The initial sulfur content in the model oil is 300 mg·kg-1 （thiophene ＂ DI3T= 1 ＂ 1）. After 10 h of treatment, the thiophene concentration is reduced by 40%, while DBT is reduced by 25%. The utilization rate of thiophene is faster than that of DBT. Moreover, the oil/water ratio of alginate immobilized cells is studied to reduce the water volume in desulfurization systems. Long-term recycling of BDS by alginate immobilized cells is carried out with oil/water ratio at 5 ： 1. The immobilized cells are successfully reused over 15 batch cycles. In the last batch, the desulfurization activity remains at least 75% of the first batch.展开更多
Aims Alpine forest gaps can control understory ecosystem processes by manipulating hydrothermal dynamics.Here,we aimed to test the role of alpine forest gap disturbance on total phenol loss(TPL)from the decomposing li...Aims Alpine forest gaps can control understory ecosystem processes by manipulating hydrothermal dynamics.Here,we aimed to test the role of alpine forest gap disturbance on total phenol loss(TPL)from the decomposing litter of two typical shrub species(willow,Salix paraplesia Schneid.,and bamboo,Fargesia nitida(Mitford)Keng f.).Methods We conducted a field litterbag experiment within a representative fir(Abies faxoniana Rehd.)forest based on‘gap openness treatments’(plot positions in the gap included the gap center south,gap center north,canopy edge,expanded edge and closed canopy).The TPL rate and litter surface microbial abundance(fungi and bacteria)of the two shrub species were measured during the following periods over 2 years:snow formation(SF),snow cover(SC),snow melting(ST),the early growing season(EG)and the late growing season(LG).Important Findings At the end of the study,we found that snow cover depth,freeze–thaw cycle frequency and the fungal copies g−1 to bacterial copies g−1 ratio had significant effects on litter TPL.The abundances of fungi and bacteria decreased from the gap center to the closed canopy during the SF,SC,ST and LG periods and showed the opposite trend during the EG periods.The rate of TPL among plot positions closely followed the same trend as microbial abundance during the first year of incubation.In addition,both species had higher rates of TPL in the gap center than at other positions during the first winter,first year and entire 2-year period.These findings suggest that alpine forest gap formation accelerates litter TPL,although litter TPL exhibits dual responses to gap disturbance during specific critical periods.In conclusion,reduced snow cover depth and duration during winter warming under projected climate change scenarios or as gaps vanish may slow litter TPL in alpine biomes.展开更多
基金Supported by the National Natural Science Foundation of China (21076216,30970046)
文摘Biodesulfurization （BDS） is a promising technology for deep desulfurization. In this work, Pseudomonas delafieldii R-8 cells are immobilized in calcium alginate beads and used for BDS of transportation fuels. It is found that thiophene and dibenzothiophene （DBT） can be simultaneously metabolized by immobilized R-8 cells. The initial sulfur content in the model oil is 300 mg·kg-1 （thiophene ＂ DI3T= 1 ＂ 1）. After 10 h of treatment, the thiophene concentration is reduced by 40%, while DBT is reduced by 25%. The utilization rate of thiophene is faster than that of DBT. Moreover, the oil/water ratio of alginate immobilized cells is studied to reduce the water volume in desulfurization systems. Long-term recycling of BDS by alginate immobilized cells is carried out with oil/water ratio at 5 ： 1. The immobilized cells are successfully reused over 15 batch cycles. In the last batch, the desulfurization activity remains at least 75% of the first batch.
基金supported by the National Natural Science Foundation of China(no.31570445 and 31800518).
文摘Aims Alpine forest gaps can control understory ecosystem processes by manipulating hydrothermal dynamics.Here,we aimed to test the role of alpine forest gap disturbance on total phenol loss(TPL)from the decomposing litter of two typical shrub species(willow,Salix paraplesia Schneid.,and bamboo,Fargesia nitida(Mitford)Keng f.).Methods We conducted a field litterbag experiment within a representative fir(Abies faxoniana Rehd.)forest based on‘gap openness treatments’(plot positions in the gap included the gap center south,gap center north,canopy edge,expanded edge and closed canopy).The TPL rate and litter surface microbial abundance(fungi and bacteria)of the two shrub species were measured during the following periods over 2 years:snow formation(SF),snow cover(SC),snow melting(ST),the early growing season(EG)and the late growing season(LG).Important Findings At the end of the study,we found that snow cover depth,freeze–thaw cycle frequency and the fungal copies g−1 to bacterial copies g−1 ratio had significant effects on litter TPL.The abundances of fungi and bacteria decreased from the gap center to the closed canopy during the SF,SC,ST and LG periods and showed the opposite trend during the EG periods.The rate of TPL among plot positions closely followed the same trend as microbial abundance during the first year of incubation.In addition,both species had higher rates of TPL in the gap center than at other positions during the first winter,first year and entire 2-year period.These findings suggest that alpine forest gap formation accelerates litter TPL,although litter TPL exhibits dual responses to gap disturbance during specific critical periods.In conclusion,reduced snow cover depth and duration during winter warming under projected climate change scenarios or as gaps vanish may slow litter TPL in alpine biomes.
