Lignocellulosic biomass is an abundant and renewable bioresource for the production of biofuels and biochem-ical products.The classical biorefinery process for lignocellulosic degradation and conversion comprises thre...Lignocellulosic biomass is an abundant and renewable bioresource for the production of biofuels and biochem-ical products.The classical biorefinery process for lignocellulosic degradation and conversion comprises three stages,i.e.,pretreatment,enzymatic saccharification,and fermentation.However,the complicated pretreatment process,high cost of cellulase production,and insufficient production performance of fermentation strains have restricted the industrialization of biorefinery.Consolidated bioprocessing(CBP)technology combines the pro-cess of enzyme production,enzymatic saccharification,and fermentation in a single bioreactor using a specific microorganism or a consortium of microbes and represents another approach worth exploring for the production of chemicals from lignocellulosic biomass.The present review summarizes the progress made in research of CBP technology for lignocellulosic biomass conversion.In this review,different CBP strategies in lignocellulose biore-finery are reviewed,including CBP with natural lignocellulose-degrading microorganisms as the chassis,CBP with biosynthetic microorganisms as the chassis,and CBP with microbial co-culturing systems.This review provides new perspectives and insights on the utilization of low-cost feedstock lignocellulosic biomass for production of biochemicals.展开更多
Fermentation of cellulosic biomass can be done in a single step with cellulolytic, solventogenic bacteria, such as Clostridium thermocellum. However, the suite of products is limited in consolidated bioprocessing. For...Fermentation of cellulosic biomass can be done in a single step with cellulolytic, solventogenic bacteria, such as Clostridium thermocellum. However, the suite of products is limited in consolidated bioprocessing. Fortunately, the thermophilic nature of C. thermocellum can be exploited in sequential culture. Experiments were conducted to determine the effect of feedstock particle size on fermentation by sequential cultures and to demonstrate this effect could be shown by gas production. Dual-temperature sequential cultures were conducted by first culturing with C. thermocellum (63°C, 48 h) before culturing with C. beijerinckii (35°C, 24 h). Switchgrass (2, 5 or 15 mm particle size) was the feedstock in submerged substrate (10% w/v) fermentation. The extent of fermentation was evaluated by gas production and compared by analysis of variance with Tukey’s test post hoc. C. thermocellum alone produced 78 kPa cumulative pressure (approx. 680 mL gas) when the particle size was 2 or 5 mm. The C. thermocellum cultures with 15 mm feedstock particles had a mean cumulative pressure of 15 kPa after 48 h, which was less than the 2 and 5 mm treatments (P °C) and inoculated with C. beijerinckii, and the cumulative pressures were reset to ambient, cumulative pressure values as great as 70 kPa (equivalent to an additional 670 mL gas) were produced in 24 h. Again, the longer (15 mm) particle size produced less gas (P < 0.05). When the substrates were inoculated with C. beijerinckii without previous fermentation by C. thermocellum, the mean cumulative pressures were approximately 10 kPa. These results indicate that biological pretreatment with C. thermocellum increased the availability of switchgrass carbohydrates to C. beijerinckii, and that gas production is suitable method to show the effectiveness of a pretreatment.展开更多
基金supported by grants from the National Key R&D Program of China (No.2019YFA0905700)the National Natural Science Foundation of China (31970071)+1 种基金the Young Scholars Program of Shan-dong Universitythe Major Basic Research of Shandong Provincial Natural Science Foundation (ZR2019ZD19).
文摘Lignocellulosic biomass is an abundant and renewable bioresource for the production of biofuels and biochem-ical products.The classical biorefinery process for lignocellulosic degradation and conversion comprises three stages,i.e.,pretreatment,enzymatic saccharification,and fermentation.However,the complicated pretreatment process,high cost of cellulase production,and insufficient production performance of fermentation strains have restricted the industrialization of biorefinery.Consolidated bioprocessing(CBP)technology combines the pro-cess of enzyme production,enzymatic saccharification,and fermentation in a single bioreactor using a specific microorganism or a consortium of microbes and represents another approach worth exploring for the production of chemicals from lignocellulosic biomass.The present review summarizes the progress made in research of CBP technology for lignocellulosic biomass conversion.In this review,different CBP strategies in lignocellulose biore-finery are reviewed,including CBP with natural lignocellulose-degrading microorganisms as the chassis,CBP with biosynthetic microorganisms as the chassis,and CBP with microbial co-culturing systems.This review provides new perspectives and insights on the utilization of low-cost feedstock lignocellulosic biomass for production of biochemicals.
文摘Fermentation of cellulosic biomass can be done in a single step with cellulolytic, solventogenic bacteria, such as Clostridium thermocellum. However, the suite of products is limited in consolidated bioprocessing. Fortunately, the thermophilic nature of C. thermocellum can be exploited in sequential culture. Experiments were conducted to determine the effect of feedstock particle size on fermentation by sequential cultures and to demonstrate this effect could be shown by gas production. Dual-temperature sequential cultures were conducted by first culturing with C. thermocellum (63°C, 48 h) before culturing with C. beijerinckii (35°C, 24 h). Switchgrass (2, 5 or 15 mm particle size) was the feedstock in submerged substrate (10% w/v) fermentation. The extent of fermentation was evaluated by gas production and compared by analysis of variance with Tukey’s test post hoc. C. thermocellum alone produced 78 kPa cumulative pressure (approx. 680 mL gas) when the particle size was 2 or 5 mm. The C. thermocellum cultures with 15 mm feedstock particles had a mean cumulative pressure of 15 kPa after 48 h, which was less than the 2 and 5 mm treatments (P °C) and inoculated with C. beijerinckii, and the cumulative pressures were reset to ambient, cumulative pressure values as great as 70 kPa (equivalent to an additional 670 mL gas) were produced in 24 h. Again, the longer (15 mm) particle size produced less gas (P < 0.05). When the substrates were inoculated with C. beijerinckii without previous fermentation by C. thermocellum, the mean cumulative pressures were approximately 10 kPa. These results indicate that biological pretreatment with C. thermocellum increased the availability of switchgrass carbohydrates to C. beijerinckii, and that gas production is suitable method to show the effectiveness of a pretreatment.
