β-Amylase is one of the key enzymes required for complete starch hydrolysis. It is of industrial importance, particularly in the production of malt sugar and preparation of fermented foods and alcoholic beverages. The activity of β-amylase increases with the temperature up to the optimum of 60°C. Above this temperature however, enzyme denaturation becomes dominant and the conversion rate decreases. Therefore, β-amylase that retains maximum activity even at increased temperatures will be invaluable in industrial scale applications.

A group of researchers from Taiwan has developed transgenic potato lines expressing thermostable b-amylase. The scientists targeted the expression of four chimeric gene, isolated from thermophilic bacteria, in the cytoplasm, amylopast (starch-storing organelle) and vacuole. Twenty three transgenic potato lines accumulated high levels of β-amylase. In field trials however, discernible adverse effects on tuber development and formation were observed in these lines, which may be caused by alternation of metabolite composition. The researchers are currently looking for ways to minimize the effects of transgene insertion in tuber qualities.

Read the paper published by the journal Plant Science at http://dx.doi.org/10.1016/j.plantsci.2008.04.001.