Potential of L-phenylalanine Production from Raw Glycerol of Palm Biodiesel Process by a Recombinant Escherichia coli

The possibility of using raw glycerol from biodiesel process for the bacteria growth and L-phenylalanine production using recombinant Escherichia coli BL21(DE3) was investigated. Raw glycerol with 75.50% (w/w) glycerol content was pretreated with concentrated sulfuric acid to reduce the impurities. Type A and type B glycerol containing 91.28% and 83.93% glycerol content were obtained after the acid pretreatment. Raw glycerol, type A and B glycerol and commercial grade glycerol (99.5%) at various concentrations (5, 10, 30 and 50 g/L) were used as a carbon source. The cell dry weight (CD W) and L-phenylalanine concentration obtained after 36 h of cultivation from raw glycerol were much higher than that from other types of glycerol. The highest CDW (3.47 g/L) and L-phenylalanine (55.2 mg/L) were obtained from the medium containing 30 g/L of raw glycerol. The results indicated that raw glycerol from biodiesel process was an interesting carbon source for L-phenylalanine production.