Biodegradation of shea nut cake by indigenous soil bacteria

Abstract

In response to the quest for an environmentally friendly mode of disposal of shea nut cake, One hundred and sixty two (162) soil samples were collected at random at 0-20 cm, 20-40 cm and 40-60 cm soil depth from shea nut cake dumping sites in Jusonayilli, Gurugu and Kasalgu within the Sanaregu District of the Northern Region of Ghana, from September, 2010 to July, 2011. This is to isolate bacteria with high shea nut cake degrading ability and consequently select the potential application of these bacteria in bioremediation. The bacteria were grown in mineral salt medium supplemented with 2% shea nut cake as sole source of carbon. More Gram negative bacteria were involved in shea nut cake degradation than Gram positive bacteria. Two isolates which gave good growth on 5% shea nut cake agar were identified biochemically as Pseudomonas species. Both grew optimally at 35^oC and at pH 7.0. Yeast extracts enhanced growth. Pseudomanas strain G9 degraded 71.25% shea nut cake, while Pseudomonas strain G38 degraded 50.35% shea nut cake within 48 h. Pseudomonas G9 can be used to degrade shea nut cake. G9 and G38 are different species of Pseudomonas and molecular typing such as PCR can be used to determine the exact spe-cies.

Keywords: Shea nut cake, selective isolation, biodegradation, bacteria