265 Separation Process of 5-Aminolevulinic Acid from Rhodobacter spaeroides for Increasing Value of Agricultural Product by Ion Exchange Chromatography P. Tripetch Program in Biotechnology Faculty of Science Chulalongkorn University Phayathai Road, Patumwan Bangkok 10330 Thailand G. Srzednicki Food Science and Technology School of Chemical Engineering University of New South Wales Sydney 2052, NSW Australia C. Borompichaichartkul Department of Food Technology Faculty of Science Chulalongkorn University Phayathai Road, Patumwan Bangkok 10330 Thailand Keywords: 5-aminolevulinic acid (ALA), Rhodobacter spaeroides, ion exchange chromatography Abstract 5-Aminolevulinic acid (ALA) is an amino acid which is a key precursor in the biosynthesis of all porphyrin compounds. ALA has wide applications in medicine and agriculture. The photosynthetic bacterium, Rhodobacter sphaeroides, is often used for biological ALA production. However, the ALA from the biological process is often contaminated with saccharides, protein, amino acids, organic acids, metal ions that are coexisting in the fermentation broth. One of methods that is used to separate ALA from crude solution is ion-exchange chromatography (IEC). Usually, strong cation resin is employed as the media base to ALA separate process. However, stability of ALA depend on pH (2-5) and temperature (<30°C). This study aimed at studying suitable conditions to decolorisation process and pH of eluent for performance of IEC separation. The results showed that decolorisation of the fermentation broth at an initial pH of 5 using activated carbon powder and shaking for 10 min could achieve >90% of decolorisation and increase efficiency of ALA separation. The two eluents, acetate buffer 1 M (pH 4.67) and acetate buffer 1 M (pH 3.8) can increase yield of ALA (>70%) and period of elution process is 100 min. The presence of ALA was confirmed by thin layer chromatography. Yellow spot was present when ALA has reacted with ninhydrin. INTRODUCTION 5-Aminolevulinic acid (ALA) is a hydrophilic molecule which is present in all living cells. It is a precursor of all porphyrin compounds. Currently, ALA is used in various fields. In medicine, ALA can be used to destroy malignant cells in photodynamic diagnosis and therapy (Fukuda et al., 2005). In biotechnology, ALA can be applied in vitamin B12 production, plant cell, yeast, fungi and bacterial culture (Nakayashiki and Inokuchi, 1996; Bykhovsky et al., 1997; Fujita et al., 1997; Miyachi et al., 1998; Sasaki et al., 2002). In agriculture, ALA is the natural photodynamic compound effective as a biodegradable herbicide and insecticide when used at high concentration (>10 mM). Moreover, ALA appears to act as a hormone-like plant growth regulator. ALA at low concentrations can improve plant growth, yield (Hotta et al., 1997; Watanabe et al., 2000; Richter et al., 2010) and antioxidant level in pakchoi and ginkgo leaf (Nishihara et al., 2003; Memon et al., 2009; Xu et al., 2009). ALA is harmless for crops, human, animals Proc. Second Asia Pacific Symp. on Postharvest Research, Education and Extension Eds.: H.K. Purwadaria et al. Acta Hort. 1011, ISHS 2013