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Temperature effects on biomass, geosmin, and 2-methylisoborneol production and cellular activity by Nocardia spp. and Streptomyces spp. isolated from rainbow trout recirculating aquaculture systems
- Schrader, Kevin K., Harries, Marcuslene D., Page, Phaedra N.
- Journal of industrial microbiology & biotechnology 2015 v.42 no.5 pp. 759-767
- 2-methylisoborneol, Nocardia, Oncorhynchus mykiss, Streptomyces albidoflavus, adenosine triphosphate, biomass production, gas chromatography, geosmin, mass spectrometry, microbial activity, off flavors, recirculating aquaculture systems, solid phase microextraction, water temperature
- Isolates of Nocardia cummidelens, Nocard ia fluminea, Streptomyces albidoflavus, and Streptomyces luridiscabiei attributed as the cause of “earthy-musty” off-flavor in rainbow trout (Oncorhynchus mykiss) raised in recirculating aquaculture systems (RAS) were evaluated for the effect of temperature (10–30 °C) on biomass, geosmin, and 2-methylisoborneol (MIB) production and cellular activity. Cultures of these isolates were monitored over 7 days by measuring culture dry weight, geosmin, and MIB production using solid-phase microextraction-gas chromatography-mass spectrometry (SPME–GC–MS), and ATP production via a luminometer. Compared to the other isolates, S. luridiscabiei had significantly (P < 0.05) higher biomass (8.17 ± 0.35 mg/mL) at 15 °C (water temperature in the RAS) after 7 days incubation. In addition, S. luridiscabiei produced significantly (P < 0.05) higher geosmin (69,976 ± 15,733 ng/L) at 15 °C. At 25 °C and 30 °C, S. albidoflavus produced significantly (P < 0.05) higher geosmin (182,074 ± 60,272 ng/L and 399,991 ± 102,262 ng/L, respectively). All isolates produced MIB at 15 °C, but S. luridiscabiei produced significantly (P < 0.05) higher MIB (97,143 ± 28,972 ng/L) and ATP after 7 days. Therefore, S. luridiscabiei appears to be a likely contributor of geosmin and MIB in the RAS.