Organosolv pretreatment for enzymatic hydrolysis of poplars: I. enzyme hydrolysis of cellulosic residues

Journal Article · Fri Jan 01 04:00:00 EST 1988 · Biotechnol. Bioeng.; (United States)

DOI:https://doi.org/10.1002/bit.260310703· OSTI ID:6929947

Chum, H L; Johnson, D K; Black, S; Baker, J; Grohmann, K; Sarkanen, K V; Wallace, K; Schroeder, H A

Aspen (Populus tremuloides) and black cottonwood (Populus trichocarpa) organosolv pulps produced in a wide range of solvent composition (between 30 and 70% by volume of methanol) and catalysts (H/sub 2/SO/sub 4/ and H/sub 3/PO/sub 4/) such that the cooking liquor pH less than or equal to 3 are easily digested by enzymes. The total yields of hydrolysis residues (pulps) are in the 40-60% range; the acid-catalyzed delignification followed by enzyme hydrolysis can generate 70-88% of the original six-carbon sugars contained in the wood. Glucomannan and arabinogalactan are dissolved in to the pulping liquor in the pH range of 2-4.5. Lower pH (less than or equal to 3) leads to additional solubilization of six-carbon sugars. These sugars may be fermented directly. From the insoluble hydrolysis residues, 36-41% conversions of wood into fermentable sugars were obtained after enzyme hydrolysis; the starting feedstocks contain 50.8 and 46.6% hexosans, respectively, for aspen and black cottonwood. The kinetics of enzymatic hydrolysis of cellulose can be formally treated as two simultaneous pseudo-first-order reactions in which fast and slow hydrolysis of cellulose occur. Correlations between the glucan digestibility and the effect of the pretreatment have been made. The higher residual xylan content reduces the amount of the rapidly hydrolyzable glucan fraction and lowers the glucan digestibility. The proposed simple kinetic treatment is very helpful in assessing the effect of the pretreatment on pulp enzyme hydrolyzability.

• Research Organization: Solar Energy Research Institute, Golden, CA (USA)
• OSTI ID: 6929947
• Journal Information: Biotechnol. Bioeng.; (United States), Journal Name: Biotechnol. Bioeng.; (United States) Vol. 31:7; ISSN BIBIA
• Country of Publication: United States
• Language: English

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BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
CARBOHYDRATES
CELLULOSE
CHEMICAL REACTIONS
DECOMPOSITION
ENZYMATIC HYDROLYSIS
FUELS
HYDROLYSIS
KINETICS
LYSIS
ORGANIC COMPOUNDS
PLANTS
POLYSACCHARIDES
POPLARS
REACTION KINETICS
RESOURCE POTENTIAL
SACCHARIDES
SOLVOLYSIS
SYNTHESIS
SYNTHETIC FUELS
TREES