Evaluation of Cassava (Manihot esculenta) and Sweet Potato (Ipomea batatas) Starch from South East Nigeria in the Separation of Deoxyribonucleic Acids as Alternative to Agarose Gel

Gel electrophoresis technique is an indispensable tool in biotechnology and among other related fields for separation of nucleic acids and proteins. This study determined the potential of selected cassava and sweet potato starch in the separation of DNA as alternative to agarose gel. The sample pH, gelling temperature and time were determined by Light transmittance method proposed by Craig et al. [1] Standard electrophoresis procedure was used for the starch gel electrophoresis. The result showed that composite starch gelled within 18-21 minutes while agarose and agar-agar gelled after 12 minutes.  Cassava starch blended with agar-agar gelled at a temperature of 58oC while sweet potato starch blended with agar-agar gelled between 35oC - 47oC. Agarose and agar-agar maintained 54oC and 53oC respectively. There was no significant difference (P > 0.05) in pH value of the composite starch when compared to 1% agarose gel. Unblended starch samples did not form solid gel except when blended with some amount of agar-agar or agarose powder. Cassava and sweet potato composite starch formed good gel strength at 3% (2.2 g of starch and 0.8 g of agar-agar) but solid gel at 4% (3.6 g of starch and 0.8 g of agar-agar). This study demonstrated the possibilities for agarose cost reduction by 60% when cassava starch (3.6 g) was blended with 0.4 g of agarose. The cassava composite starch (4%) separated DNA molecules comparably to that of 1% agarose. Therefore, the use of these cheaper, accessible and readily available blended starch sources is highly recommended for separation of biomolecules such as DNA.