Enhancement of starch conversion efficiency with free and immobilized pullalanase and alpha-1,4 glucosidase

Journal Article · Mon Feb 01 04:00:00 EST 1982 · Biotechnol. Bioeng.; (United States)

OSTI ID:7072039

Kumar, A R; Venkatasubramanian, K

Glucoamylase and pullulanase were immobilized on reconstituted bovine-hide collagen membranes using the covalent azide linkage method. A pretanning step was incorporated into the immobilization procedure to enable the support matrix to resist proteolytic activity while accommodating an operating temperature of 50 degrees Celcius. The immobilized glucoamylase and pullulanase activities were 0.91 and 0.022 mg dextrose equivalent (DE) min-1 cm-2 of membrane, respectively. Immobilized glucoamylase had a half-life of 50 days while the immobilized pullulanase had a half-life of 7 days. This is a considerably improved stability over that reported by other researchers. The enzymes were studied in their free and immobilized forms on a variety of starch substrates including waxy maize, a material which contains 80% alpha-1-6-glucosidic linkages. Substrate concentrations ranged from 1% to a typical commercial concentration of 30%. Conversion efficiencies of 90-92% DE were obtained with free and immobilized glucoamylase preparations. Conversion enhancements of 4-5 mg of DE above this level were obtained by the use of pullulanase in its free or immobilized forms. Close examination of free pullulanase stability as a function of pH indicated improved thermal stability at higher pH values. At 50 degrees Celcius and pH 5.0, the free enzyme was inactivated after 24 hours. At pH 7.0, the enzyme still possessed one-half its activity after 72 hours. Studies were conducted in both batch and continuous total recycle reactors. All experiments were conducted at 50 degrees Celcius. Experiments conducted with coimmobilized enzymes proved quite promising. Levels of conversion equivalent to those obtained with the individually immobilized enzymes were realized. (Refs. 16).

• Research Organization: Dept Chemical and Biochemical Engineering, Rutgers Univ New Brunswick, NJ 08903
• OSTI ID: 7072039
• Journal Information: Biotechnol. Bioeng.; (United States), Journal Name: Biotechnol. Bioeng.; (United States) Vol. 24:2; ISSN BIBIA
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
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59 BASIC BIOLOGICAL SCIENCES
BATCH CULTURE
BIOCONVERSION
CARBOHYDRATES
CEREALS
CONTINUOUS CULTURE
CULTURE MEDIA
ENZYME ACTIVITY
ENZYMES
GLUCOSIDASE
GLYCOSYL HYDROLASES
GRAMINEAE
GRASS
HYDROLASES
IMMOBILIZED ENZYMES
MAIZE
MEMBRANES
O-GLYCOSYL HYDROLASES
ORGANIC COMPOUNDS
PH VALUE
PLANTS
POLYSACCHARIDES
REAGENTS
SACCHARIDES
SAMPLE PREPARATION
STABILITY
STARCH
SUBSTRATES