SCREENING OF MEDIUM COMPOSITIONS FOR RECOMBINANT LIPASE PRODUCTION VIA TWO-LEVEL FRACTIONAL FACTORIAL DESIGN

Abstract

The demand for lipase in the food and detergent industries is gradually increasing with the human
population. Therefore, the production of recombinant lipase is an alternative to accommodate the high
supply-demand caused. Large-scale enzymatic production aims to produce a maximum yield with a
minimum, medium cost. An experimental design using a two-level fractional factorial design (2k-1 FFD)
was conducted at a laboratory scale. The experiment was carried out to measure and screen the effect
of five medium components as the factors, namely ammonium sulphate ((NH4)2SO4), glycerol, yeast
extract, monopotassium dihydrogen phosphate (KH2PO4) and dipotassium phosphate (K2HPO4). The
factors were exploited respectively at low and high-level parameter ranges in g/L, (NH4)2SO4 7.00
14.00; glycerol 17.50 – 35.00, yeast extract 10.00 – 20.00; KH2PO4 1.00-2.00; K2HPO4 8.25-16.50).
The combination of experimental design with 25-1 fractional factorial design reflected 16 shake flasks
of submerged fermentation of recombinant E. coli (rE. coli) harbouring recombinant lipase. Responses
of lipase and total protein yield were obtained, and the interaction between the five factors was
investigated in this study. In the finding for the lipase concentration, (NH4)2SO4 and K2HPO4 were
significant contributing factors, while only K2HPO4 was found to contribute to the total protein.
However, the Pareto plot displayed that the K2HPO4 and (NH4)2SO4 have different influences on lipase
production. Meanwhile, K2HPO4 showed a positive impact on both lipase and total protein
concentration. In the study, the maximum lipase concentration was 5.56 mg/ml with lipase activity 7.58
x 10-2 µmol/min/ml and maximum specific lipase activity was 3.01 x 10-2 µmol/min/mg. While for the
total protein, the highest concentration was 1.28 mg/ml.