ENVIRONMENTAL-EFFECTS ON THE PRODUCTION OF OKADAIC ACID FROM PROROCENTRUM-HOFFMANNIANUM FAUST .1. TEMPERATURE, LIGHT, AND SALINITY

Clonal cultures of Prorocentrum hoffmannianum Faust (clone 882a) were grown under various temperatures, light intensities, and salinities to examine changes in growth rates and okadaic acid content. The acclimated tolerance range for growth was between 21-degrees-C and 36-degrees-C. With regard to light intensity, acclimated growth was possible between 2000 and 5000 Ix. Growth rate was optimal at 27-degrees-C under 5000 lx (k = 0.53 division . day-1). Acclimated growth rate was maximum at a salinity of 34 parts-per-thousand. Okadaic acid content changed drastically with regard to temperature and light. No trends were observed between reproduction rates and okadaic acid production. Optimum okadaic acid production (58.6 pg cell-1) was achieved at 24-degrees-C under 2000 lx. A second peak in okadaic acid production (45 pg . cell-1) was observed at 29-degrees-C under 4000 Ix. Unlike temperature and light, salinity results showed an inverse trend between okadaic acid content and growth rate. These results suggest an increased okadaic acid content with increased environmental stress.