Paul Wacoo Alex and Deborah Wendiro
Uganda Industrial Research Institute, Uganda
Posters-Accepted Abstracts: J Food Process Technol
Fecal coliforms are the most important indicator of hygienic quality of water. Frequently used methods for detection of fecal coliforms such as Multiple-tube fermentation technique, membrane filtration technique and enzymatic methods are extremely time-consuming and require at least 18 hours to detect them. A rapid and very sensitive thin layer chromatography (TLC) techniques based on the detection of ortho-nitophenol, a byproduct of enzymatic breakdown of ortho-Nitrophenyl-β-D-galactopyranoside by galactosidase secreted by the fecal coliforms at 44.5oC was developed. Water (100 mL) samples spiked with fecal coliform (1 to 109 CFU) were uniformly mixed with 3.6 g of Lauryl Sulfate mixed witho-Nitrophenyl-β-D-galactopyranoside (1.0 g/L) and incubated at 44.5oC for 2 hours. ortho-Nitrophenol was extracted from each sample with 10 mL of hexane. Aliquots of 5 μL each of sample extracts were spotted on Silica Gel and plates developed in a mobile phase composed of a mixture of SDS, Water, heptane and butanol. After the chromatography ascended to the 10 cm mark, the plates were then dried with a stream of hot air (110oC). The dried plates were exposed to ammonia vapour to ease detection of o-nitrophenol spots. The TLC technique detected fecal coliforms just after 2 hours of incubation with a detection limit of 1 CFU/100 mL. This method is very sensitive, specific and can be used for rapid screening of water sources for fecal coliforms. The method can be used as a tool for quick decision making since the regulatory standards for potable water in many countries requires less than 1 colony/100mL.
Paul Wacoo Alex has just completed his MSc in Biochemistry from Makerere University and now preparing to enroll in a PhD program. He developed an electrochemical aflatoxin B1 testing kit that attracted a Young Innovator Award 2014 for East, Central and Southern Africa Organized by UN Women, FAO, ICRA, WFP among others. He is working at the Uganda Industrial Research Institute (UIRI), Section of Microbiology and Biotechnology as a Biochemist.