Abstract
Different organic substrates (maize flour, barley flour, rice flour, sawdust, wheat bran and millet grains) were used as nutrient source to Bacillus thuringiensis Berliner (B.t.) isolates (B.t.-16 and B.t.-64). The purpose of the study was to determine the most efficient organic substrate least expensive for the growth of the bacteria. All the tested substrates showed increase in growth of B.t. isolates from the first week except sawdust, which showed a decline in bacterial population in the first week but thereafter a gradual increase in bacterial population occurred till the end of the experiment. Rice, Wheat bran, and Barley flours were found to be more effective substrates for the bacterial growth. The isolate B.t.-16 appeared to possess relatively more ligninolytic potential. Based on promotion or reduction magnitude in final population sizes (on 28- day of incubation) the growth pattern of B.t.-16 and B.t.-64 on various substrates, in decreasing order of suitability, may be shown as follows: B.t.- 16 - Rice > Wheat > Barley > Maize > Millet > Sawdust B.t.- 64 –Wheat > Barley > Millet > Rice > Maize > Sawdust
