Optimized Purification of Free Amino Acids from Molasses by Nanofiltration Membrane

In this research, nanofiltration was utilized to purify free amino acids (AAs) from sugar and colloids of sugar cane molasses (SCM) and sugar beet molasses (SBM) based on their molecular weight. The impact of temperature (30-50˚C), pressure (2-7 bar), and pH (2-11) in optimizing the purification condition was evaluated using the response surface methodology. The SCM and SBM purification results revealed the same optimum conditions in both types of molasses: 47 ˚C temperature, 3 bar pressure, and 9.3-9.5 pH. In the optimum condition, the recovery values of AAs for SCM and SBM were 66% and 63% for aspartic acid, 68.5% and 66% for glutamic acid, 84% and 69% for alanine, and 82% and 69% for lysine, respectively. The total efficiency values of four AAs and flux were obtained as 75% and 70 Lm-2h-2 for SCM and 67% and 45 Lm-2h-2 for SBM, respectively. The results indicated the suitability of the nanofiltration system's purifying function for AAs from SCM and SBM with desirable selectivity and purification efficiency.