Growth and viability of Alcaligenes eutrophus JMP134 in seawater as affected by substrate and nutrient amendment

Growth and viability of Alcaligenes eutrophus JMP134 was studied in laboratory microcosms with 0.2 microns-filtered seawater prior to release in field-based mesocosms. In unamended systems JMP134 did not grow and viability, measured as direct viable counts combined with immunofluorescence microscopy, was 40-50%. Addition of a nitrogen + phosphorus nutrient mixture caused a greater growth response than amendment with a carbon substrate. Amendment with substrate and/or nutrients caused an increase in viability to ca 100% but only for a brief period coinciding with cell proliferation. Hence, Alc. eutrophus JMP134 has a limited survival potential in seawater unless it is supplied with additional nutrients.