Production of native-starch-degrading enzymes by a Bacillus firmus/lentus strain

• Published in: Applied microbiology and biotechnology Vol. 35; no. 2; pp. 180 - 184
• Main Authors: Wijbenga, D.J, Beldman, G, Veen, A, Binnema, D.J
• Format: Journal Article
• Language: English
• Published: 01.05.1991
• Subjects: alpha-amylase; alpha-glucosidase; Bacillus (bacteria); corn starch; enzyme activity; glucan 1,4-alpha-glucosidase; hydrolysis; potato starch; starch; wheat
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/BF00184683

A bacterium belonging to the Bacillus firmus/lentus-complex and capable of growth on native potato starch was isolated from sludge of a pilot plant unit for potato-starch production. Utilization of a crude enzyme preparation obtained from the culture fluid after growth of the microorganism on native starch, resulted in complete degradation of native starch granules from potato, maize and wheat at a temperature of 37 degrees C. Glucose was found as a major product. Production of maltose, maltotriose and maltotetraose was also observed. Native-starch-degrading activity (NSDA) could be selectively adsorbed on potato-starch granules, whereas soluble-starch-degrading activity (SSDA) remained mainly in solution. The use of such a starch-adsorbed enzyme preparation on native starch resulted in a completely changed product pattern. An increase in oligosaccharides concomitant with less glucose formation was observed. An increased conversion of soluble starch to maltopentaose was possible with this starch-adsorbed enzyme preparation. It is concluded that NSDA comes from alpha-amylase(s) and SSDA from glucoamylase(s) and/or alpha-glucosidase(s). Cultivation of B. firmus/lentus on glucose, maltose, or soluble starch resulted in substantially smaller quantities of (native) starch-degrading activity.