ABSTRACT

This study was conducted in order to determine the effect of selected carbohydrate sources on the vegetative growth of Daldinia concentrica. Mycelia of D. concentrica was isolated from the fruiting body. The fungi isolated were cultured on Potato dextrose agar (PDA) medium at ambient temperature 26+2⁰Cand thereafter preserved at 4⁰C. The fungus was incubated in a conical flask (250mls) with 50mls of the medium containing sucrose 6; NaNO₃, 0.3 KCl, 0.05; MgSO₄. 7H₂O_, 0.005; KH₂PO₄, 0.1; FeSO₄. 5H₂O, 0.005g/100ml at pH 6 and incubated at 30⁰C for 15 minutes then filtered through cheese cloth and supernatant mixed with two volume of ethanol (95%) and stored overnight at 5⁰C and precipitate was recovered by centrifugation at 5000xg for 10 minutes, exopolysaccharide was washed three times with 10% Trichloroacetic acid (then removed by repeated washing with acetone). The results shows that there was a significant (p˂0.05) reduction of glucose consumption by D. concentrica observe at 96 hours with a range of 4.0±1.40 - 12.0±1.37. The exopolysaccharide yields were as follows: glucose (0.955±0.50g/l), fructose (0.930±0.58g/l), sucrose (0.294±0.26g/l), maltose (0.285±0.28g/l) and starch (0.193±0.21g/l).  The mycelial biomass obtained from the different carbohydrate sources ranged from 0.94±0.80g - 2.15±1.09g respectively. This study suggests further research should be carried out to ascertain the factors such as temperature, incubation time and different substrates affecting the production of exopolysaccharide.