ARS | Publication request: ALLELIC VARIATION IN BARLEY ALPHA-GLUCOSIDASE

Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 2003
Publication Date: August 1, 2003
Citation: MUSLIN, E.H., HENSON, C.A. ALLELIC VARIATION IN BARLEY ALPHA-GLUCOSIDASE. PLANT BIOLOGY. 2003. p. 75. Abs. No. 243.

Technical Abstract: Starch degradation in barley (Hordeum vulgare) seeds results from the combined action of alpha-amylase, beta-amylase, limit dextrinase and alpha-glucosidase. The thermal stability of these enzymes is important because the conversion of barley starch to fermentable sugars during industrial ethanol production (e.g. brewing, fuel ethanol production) typically takes place at temperatures of 60-75C. At these temperatures alpha-glucosidase has less than 5% of the activity it has at 30C (Muslin et al., 2000). Thermolability of alpha-glucosidase could result in reduced efficiency of starch breakdown at these high temperatures. The increase the thermostability of alpha-glucosidase, we have created a thermostable alpha-glucosidase using site-directed mutagenesis (Muslin et al, 2002) which, when used in the industrial starch breakdown process (mashing), increased the amount of glucose produced by 29% (Muslin et al., 2003). We are now in the process of trying to find alleles in the Hordeum germplasm encoding a more thermostable enzyme. Differences in the thermostability of alpha-glucosidase were found in 7 cultivars of North American barley. These alpha-glucosidases were cloned and sequenced and single nucleotide polymorphisms (SNP) were found.