ABSTRACT
Ensilage is a traditional way of preserving fresh biomass. However, in order to apply ensilage to the ethanol biorefinery, two parameters need to be evaluated: quantity and quality changes of the biomass; and its effects on bioconversion process. To study these two aspects, switchgrass harvested on three different time points (Early, mid and late fall) were used as feedstock. The early fall harvested biomass was ensiled at 5 moisture levels ranging from 30% to 70%. Silage of 40% moisture and 3 other raw switchgrass were pretreated with liquid hot water, followed by enzymatic hydrolysis as well as simultaneous saccharification and fermentation. After 21 days storage pH values of all silages decreased below 4.0 and the dry matter losses were less than 2.0%, and structural sugars contents did not change dramatically. Liquid hot water caused more hemicellulose dissolution in the silage than in unensiled switchgrass. However, ensilage also increased the risk of releasing more sugar degradation products; After enzymatic hydrolysis, silage obtained higher total glucose, xylose and galactose yields than raw materials; After simultaneous saccharification and fermentation, ethanol concentration in silage was 12.1 g/L, higher than the unensiled switchgrass (10.3 g/L, 9.7 g/L and 10.6 g/L for early, mid and late fall respectively). Our results suggest that ensilage helps increase pretreatment efficiency and sugar yield, which increases final ethanol production.
Subject(s)
Biomass , Ethanol , Chemistry , Fermentation , Galactose , Chemistry , Glucose , Chemistry , Hot Temperature , Hydrolysis , Panicum , Chemistry , Polysaccharides , Chemistry , Silage , Water , Xylose , ChemistryABSTRACT
Cellulosic ethanol, with the advantages of renewable resource, cleanliness and safety, is the mainstream of new energy development and has obtained extensive attention worldwide. In this review, the biological characteristics of beets were introduced, and then the superiority and application progress of beets and its by-product sugar beet pulp in the bioethanol production were stated. At last, cellulosic ethanol production coupled with the component separation and comprehensive utilization of beet pulp was proposed.
Subject(s)
Beta vulgaris , Chemistry , Biofuels , Cellulose , Chemistry , Ethanol , ChemistryABSTRACT
United States is a big biofuels market and a dominant country in the research and development of advanced biofuels.It has set up an ambitious development goal and strong supportive policy measures for advanced biofuels,and implemented the Biomass Program,currently focusing on the research,development and demonstration of cellulosic biofuels,and also embarking upon the research of third generation biofuels.US government attaches great importance to related planning,analyses and inter-agency cooperation.On the basis of the progresses on the frontiers of basic and applied research,it has been vigorously advancing the demonstration and commercialization of biofuels technology,in an effort to accelerate the transition to advanced biofuels.