Efficient Extraction of Lycopene from Rhodopseudomonas palustris with n-Hexane and Methanol after Alkaline Wash

Extraction of lycopene from Rhodopseudomonas palustris with various solvents and alkaline wash was investigated. Dichloromethane or benzene as single polar or nonpolar solvent were the most effective solvents. The maximum extraction efficiency was achieved with a combination of n-hexane and methanol (1:1 v/v). which was approximately one time higher than that obtained with a single solvent. The partitioning behavior of lycopene in n-hexane/methanol indicated that almost all extracted lycopene from R. palustris cells was dissolved in the n-hexane phase. Further studies showed that lycopene extraction was much improved after an alkaline wash of R. palustris cells. The measured lycopene content was much higher than that in tomatoes which indicates that R. palustris will become an important biological resource of lycopene.