Isolation of Biofilm-Bioflocculant Producing Bacteria from Palm Oil Mill Effluent

A variety of flocculants have been used to treat wastewater by agglomerating various colloidal substances and cells. Due to the adverse effects and high cost of conventional flocculants, bioflocculant which are originally produced by microorganisms are gaining attention. Therefore, this study aimed to identify the biofilm-bioflocculant-producing bacteria which was isolated from palm oil mill effluent in Johor, Malaysia. The isolated bacteria were identified by their colony morphology, Gram-staining and 16S rRNA gene sequence analysis. All isolates were subjected to bioflocculant assay with kaolin clay suspension as a model of wastewater to assess the flocculation efficiency of the bacterial bioflocculants. Two different isolates were successfully identified as Gram-negative bacteria Stenotrophomonas koreensis TR6-01 and Alishewanella agri BL06. S. koreensis TR6-01 shows the highest flocculating activity at 82.79%, followed by A. agri BL06 with 78.52%, respectively. The strongest biofilm producer was shown by S. koreensis TR6-01 and thus, indicates good candidate for future wastewater treatment technology.