Tom Felix Juma, Gicharu Gibson Kamau, Gona Makenzi Nzaro, Chimbevo Lenny Mwagandi, Mjomba Fredrick Mwamburi, Amana Mzee Juma

ABSTRACT

Chlorfenvinphos is one of the Organophosphates largely produced around the world to control mites and ticks in dairy farming. However, it is toxic to human health through adverse effects on the nervous system and potential harm to other organ systems and have a long residual effect posing risks to both aquatic and terrestrial ecosystems. This study aimed at optimizing pH and temperature and Screening for chlorfenvinphos degrading organophosphorus phosphatase enzymes from three chlorpyrifos-degrading bacterial isolates, namely Advenellakashmirensis,Micrococcusluteus,and Lysinibacillus sphaericus. The bacteria were grown at varying pH and temperature. Results indicated different growth rates as indicated by optical density (OD) values taken at different pH and temperature. Advenella kashmirensis exhibited the highest growth while Lysinibacillussphaericushad the lowest. The optimal conditions for growth were determined to be at pH 7 and 35°C, resulting in an optical density (OD) of 0.132 for Lysinibacillus sphaericus. For Advenella kashmirensis, the optimum conditions were identified at pH 6 and 35°C, yielding an OD of 0.175. Micrococcus luteus demonstrated maximal growth at pH 7 and 35°C, attaining an OD of 0.106. When analyzed for crude protein concentration, A. kashmirensis exhibited the highest crude protein concentration (465.407±31.820 μg/mL) followed by L. sphaericus (303.556±20.368 μg/mL) and lastly M. luteus (292.074±8.373 μg/mL). A. kashmirensis exhibited highest crude protein concentration (465.407±31.820 μg/mL) and was significantly different at P < 0.05. This, suggest that Advenellakashmirensisis suitable for applications requiring high concentrations of total proteins compared to the two. Enzyme activity increased after purification steps particularly through ammonium sulfate precipitation and gel filtration with A. kashmirensis exhibiting the highest enzyme activity after gel filtration (19.761±0.818 µMol/Min in Fraction I), followed by M.luteus(13.772±0.979 µMol/Min in Fraction I) and L.sphaericus(11.808±0.181 µMol/Min in Fraction I) among the three Advenella kashmirensis had the highest activity (19.761±0.818 µMol/Min and was significantly different at P < 0.05.Therefore A. kashmirensis can be applied for bioremediation applications. However, future studies should explore the potential applications of these organophosphorus phosphatase enzymes obtained from A. kashmirensis, M. luteus, and L. sphaericus in chlorfenvinphos degradation for use in bioremediation, this would provide practical implementation.