Control of Cyanobacteria and Degradation of the Produced Microcystin by Aquatic Bacteria Isolated from Some Water Sources in Chiang Mai Province

Abstract

Blooms of toxin-producing cyanobacteria generally occur in natural water resources. Some cyanobacteria produce microcystin, which is extremely toxic to many organisms including humans. This work was to control the growth of Dolichospermum sp. AARL C014 and Microcystis sp. AARL C028, as well as to degrade microcystin by bacteria isolated from the water and sediments in reservoir of Mae Kuang Udomtara Dam Reservoir and Chiang Mai Moat in Chiang Mai province. Thirty seven bacterial isolates were obtained. They were tested for controlling the growth of Dolichospermum sp. AARL C014
and Microcystis sp. AARL C028 in liquid BG-11 medium. It was shown that isolate WMK06 100% inhibited Dolichospermum sp. AARL C014 on Day 3 and 57% inhibited Microcystis sp. AARL C028 on Day 14. Study on the biodegradation of microcystin-LR showed that WMK01 could degrade 50% of the toxin on Day 3 of the experiment.