Coenzyme Q10(CoQ10)is the most consumed dietary supplement and mainly biosynthesized by aerobic fermentation of Rhodobacter sphaeroides(R.sphaeroides).Oxygen supply was identified as a bottleneck for improving CoQ10 y...Coenzyme Q10(CoQ10)is the most consumed dietary supplement and mainly biosynthesized by aerobic fermentation of Rhodobacter sphaeroides(R.sphaeroides).Oxygen supply was identified as a bottleneck for improving CoQ10 yield in R.sphaeroides.In this study,a precise regulation strategy based on dielectric spectroscopy(DS)was applied to further improve CoQ10 biosynthesis by R.sphaeroide.First,a quantitative response model among viable cells,cell morphology,and oxygen uptake rate(OUR)was established.DS could be used to detect viable R.sphaeroides cells,and the relationship among cell morphology,CoQ10 biosynthesis,and OUR was found to be significant.Based on this model,the online specific oxygen consumption rate(QO2)control strategy was successfully applied to the CoQ10 fermentation process.QO2 controlled at 0.07±0.01×10−7mmol/cell/h was most favorable for CoQ10 biosynthesis,resulting in a 28.3%increase in CoQ10 production.Based on the multi-parameters analysis and online QO2 control,a precise online nutrient feeding strategy was established using conductivity detected by DS.CoQ10 production was improved by 35%,reaching 3384 mg/L in 50 L bioreactors.This online control strategy would be effectively applied for improving industrial CoQ10 production,and the precise fermentation control strategy could also be applied to other fermentation process.展开更多
In some industrial plants, wastewater was intermittently or seasonally generated. There may be periods during which wastewater treatment facilities have to be set into an idle phase over several weeks. When wastewater...In some industrial plants, wastewater was intermittently or seasonally generated. There may be periods during which wastewater treatment facilities have to be set into an idle phase over several weeks. When wastewater was generated again, the activated sludge flocs may have disintegrated. In this experiment, re-activation characteristics of aerobic granular sludge starved for 2 months were investigated. Specific oxygen utilization rate(SOUR) was used as an indicator to evaluate the metabolic activity of the sludge. The results revealed that aerobic granular sludge could be stored up to two months without running the risk of losing the integrity of the granules and metabolic potentials. The apparent color of aerobic granules stored at room temperature gradually turned from brownish-yellowish to gray brown. They appeared brownish-yellowish again 2 weeks after re-activation. The velocity and strength of granules after 2-month idle period could be fully restored about 3 weeks after re-activation. Metabolic activity, however, dropped to 15 8 mg O_2/(g MLVSS·h), i.e. 74 % reduction after 2 months of storage. After restarting the reactor, it took 2 weeks that SOUR of up to 48 5 mg O_2 /(g MLVSS·h) was achieved. A stable effluent COD concentration of less than 150 mg/L was achieved during the re-activation process.展开更多
基金supported by the financial support of research projects from the National Key R&D Program of China(No.2021YFC2101000)Shanghai Scientific and Technological Innovation Action Plans-Scientific Instrument Development,China(grant No.21142201300,22142201000)+1 种基金National Natural Science Foundation of China(No.32071471 and No.22078295)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX21_2866).
文摘Coenzyme Q10(CoQ10)is the most consumed dietary supplement and mainly biosynthesized by aerobic fermentation of Rhodobacter sphaeroides(R.sphaeroides).Oxygen supply was identified as a bottleneck for improving CoQ10 yield in R.sphaeroides.In this study,a precise regulation strategy based on dielectric spectroscopy(DS)was applied to further improve CoQ10 biosynthesis by R.sphaeroide.First,a quantitative response model among viable cells,cell morphology,and oxygen uptake rate(OUR)was established.DS could be used to detect viable R.sphaeroides cells,and the relationship among cell morphology,CoQ10 biosynthesis,and OUR was found to be significant.Based on this model,the online specific oxygen consumption rate(QO2)control strategy was successfully applied to the CoQ10 fermentation process.QO2 controlled at 0.07±0.01×10−7mmol/cell/h was most favorable for CoQ10 biosynthesis,resulting in a 28.3%increase in CoQ10 production.Based on the multi-parameters analysis and online QO2 control,a precise online nutrient feeding strategy was established using conductivity detected by DS.CoQ10 production was improved by 35%,reaching 3384 mg/L in 50 L bioreactors.This online control strategy would be effectively applied for improving industrial CoQ10 production,and the precise fermentation control strategy could also be applied to other fermentation process.
文摘In some industrial plants, wastewater was intermittently or seasonally generated. There may be periods during which wastewater treatment facilities have to be set into an idle phase over several weeks. When wastewater was generated again, the activated sludge flocs may have disintegrated. In this experiment, re-activation characteristics of aerobic granular sludge starved for 2 months were investigated. Specific oxygen utilization rate(SOUR) was used as an indicator to evaluate the metabolic activity of the sludge. The results revealed that aerobic granular sludge could be stored up to two months without running the risk of losing the integrity of the granules and metabolic potentials. The apparent color of aerobic granules stored at room temperature gradually turned from brownish-yellowish to gray brown. They appeared brownish-yellowish again 2 weeks after re-activation. The velocity and strength of granules after 2-month idle period could be fully restored about 3 weeks after re-activation. Metabolic activity, however, dropped to 15 8 mg O_2/(g MLVSS·h), i.e. 74 % reduction after 2 months of storage. After restarting the reactor, it took 2 weeks that SOUR of up to 48 5 mg O_2 /(g MLVSS·h) was achieved. A stable effluent COD concentration of less than 150 mg/L was achieved during the re-activation process.
