Pemurnian dan Karakterisasi Protein Insektisidal dari Bakteri Entomopatogen Serratia marcescens

Abstract

Insect pest control has been a major problem faced by farmers in Indonesia, and there has been no perfect solution to handle it. The use of insecticides derived from chemically active compound has made a negative impact such as the emergence of resistant pest, pest resurgence, and phenomenon of biotype. In addition, it has other negative impacts on the environment and on non-target organisms. Use of insecticidal proteins from the bacterium Serratia marcescens entomopathogenic is one potential solution in suppressing the growth of insect pests. This study aims to isolate and purify the insecticidal protein from S. marcescens and determine the level of toxicity against Tenebrio molitor larvae of insect pests. After the isolation, the insecticidal protein was purified by the method of precipitation with ammonium sulphate, dialysis, and ion exchange chromatography. It was also subjected to toxicity test using insect larvae T. molitor instar II-III as well as determination of LC50 values. The purified protein was subjected to molecular weight analysis. Results showed that the protein bands were 30.42 to 95.29 kDa. Based on the results of the study, the insecticidal protein S. marcescens is a protein toxin that is active orally with the lowest LC50 value indicated by the insecticidal protein fraction B, which is at a concentration of 4.82 ug / ml