Lime pretreatment of switchgrass

Lime (calcium hydroxide) was used as a pretreatment agent to enhance the enzymatic digestibility of switchgrass. After studying many conditions, the recommended pretreatment conditions are: time = 2 h, temperature = 100°C and 120°C, lime loading = 0.1 g Ca(OH)2/g dry biomass, water loading = 9 mL/g dry biomass. Studies on the effect of particle size indicate that there was little benefit of grinding below 20 mesh; even coarse particles (4–10 mesh) digested well. Using the recommended pretreatment conditions, the 3-d reducing sugar yield was five times that of untreated switchgrass, the 3-d total sugar (glucose + xylose) yield was seven times, the 3-d glucose yield was five times, and the 3-d xylose yield was 21 times. A material balance study showed that little glucan (approx 10%) was solubilized as a result of the lime pretreatment, whereas about 26% of xylan and 29% of lignin became solubilized.

[1]  M. G. Jackson.  Review article: The alkali treatment of straws , 1977 .

[2]  M. Holtzapple,et al.  Saccharification, fermentation, and protein recovery from low‐temperature AFEX‐treated coastal bermudagrass , 1994, Biotechnology and bioengineering.

[3]  D. Anderson,et al.  Chemical Treatment of Ryegrass Straw: Dry Matter Digestibility and Compositional Changes , 1973 .

[4]  G. L. Miller.  Use of Dinitrosalicylic Acid Reagent for Determination of Reducing Sugar , 1959 .

[5]  J. Wilkinson,et al.  Ensiled alkali-treated straw. I. Effect of level and type of alkali on the composition and digestibility in vitro of ensiled barley straw , 1978 .

[6]  T. Klopfenstein,et al.  Chemical Treatment of Wheat Straw , 1980 .

[7]  Mark T. Holtzapple,et al.  Pretreatment of lignocellulosic municipal solid waste by ammonia fiber explosion (AFEX) , 1992 .

[8]  T. Klopfenstein,et al.  Influence of Alkali Treatments of Corn Cobs on in Vitro Dry Matter Disappearance and Lamb Performance , 1976 .

[9]  Klaus D. Timmerhaus,et al.  Plant design and economics for chemical engineers , 1958 .

[10]  Cady R. Engler,et al.  Effects of cell-wall acetate, xylan backbone, and lignin on enzymatic hydrolysis of aspen wood , 1992 .

[11]  A. Klyosov.  Enzymatic conversion of cellulosic materials to sugars and alcohol , 1986 .

[12]  G. Pearce,et al.  A soak-and-press method for the alkali treatment of fibrous crop residues. Calcium hydroxide and sodium hydroxide treatments of rice straw , 1984 .

[13]  M. Playne,et al.  Increased digestibility of bagasses by pretreatment with alkalis and steam explosion , 1984, Biotechnology and bioengineering.

[14]  P. Verhonick,et al.  Time and temperature. , 1967, The American journal of nursing.

[15]  G. Pearce,et al.  Effects of chemical pretreatments on the composition and In vitro digestibility of crop by-products , 1983 .

[16]  P. Doyle,et al.  The utilization of untreated and calcium hydroxide treated wheat straw by sheep , 1985 .

[17]  T. Klopfenstein,et al.  Ammonia and/or calcium hydroxide treatment of maize stover: intake, digestibility and digestion kinetics , 1993 .

[18]  Mark T. Holtzapple,et al.  The ammonia freeze explosion (AFEX) process , 1991 .

[19]  M. Ladisch,et al.  Cellulose pretreatments of lignocellulosic substrates. , 1994, Enzyme and microbial technology.

[20]  E. Owen,et al.  Straw and other fibrous by-products as feed. , 1984 .

[21]  R. Hill,et al.  In vitro and in vivo digestibility of soya-bean straw treated with various alkalis , 1990 .

[22]  R. D. Goodrich,et al.  In vitro evaluation of chemically-treated poplar bark , 1975 .