THE USE OF YAM PEEL FOR GROWTH OF LOCALLY ISOLATED ASPERGILLUS-NIGER AND AMYLASE PRODUCTION

Yam peel was used as a carbon source to produce extracellular amylase in shake flask cultures of a thermophilic strain of Aspergillus Asperg illus niger. Peak amylase activity was obtained on the 4th day of the 6-day fermentation period which corresponded with the early stationary phase of the organism. The mycelial dry weight was not significantly affected by either yam peel or soluble starch but a higher rate of amy lase activity was obtained when the organism was grown on yam peel tha n when soluble starch was used as the sole carbon source. The optimum temperature and pH of the enzyme was 70 degrees C and 5.5, respectivel y, with more than 50% enzyme activity retained al 80 degrees C (30 min ). (C) 1997 by Elsevier Science Inc.