The optimization of culture conditions is a necessary step in biosynthesis after an expression system has been designed. This ensures that engineered microbes utilize media efficiently and ensure the healthy balance between cell growth and high expres...
The optimization of culture conditions is a necessary step in biosynthesis after an expression system has been designed. This ensures that engineered microbes utilize media efficiently and ensure the healthy balance between cell growth and high expression of recombinant protein. Green fluorescence protein (GFP) was used as a reporter gene and is not toxic to the cell, however, viral fusion peptide is known to be toxic to cell growth. In this study, we determine the culture conditions (temperature and shaking speed) which will result in optimal GFP and FP expression with high protein yield without compromising cell growth. Of the cultures studied, three batches harbored the single-plasmid co-expression system, three had the double-plasmid co-expression system and the other two served as control. Five temperature and shaking conditions were evaluated. The combination of 200 rpm and 37 ℃ gave the highest protein yield and fluorescence, however, this condition is not conducive because high expression temperatures may lead to misfolded inclusion bodies and increased proteolysis. Though 130 rpm / 23 ℃ is conducive for protein production, it gave lower fluorescence. Optimum cell growth and protein concentration patterns resulted from 170 rpm / 28 ℃ and was the most suitable out of the methods tested for dual expression of GFP and FP both in single- and double-plasmid co-expression systems.