THE FIRST REPORT OF GEOSMIN AND 2-METHYLISOBORNEOL PRODUCER CYANOBACTERIA FROM TURKISH FRESHWATERS

Abstract

Water users consider the safety of water according to its aesthetic properties, primarily taste and odour. Geosmin (GEO) and 2-methylisoborneol (MIB) are the most common taste and odour compounds in freshwaters which cause an earthy and musty odour in water. Since human nose can detect these compounds in concentrations as low as 10 ng/L, it is essential to monitor drinking waters before consumer complaints and to produce a timely solution. Therefore, it is necessary to identify GEO and MIB producers to manage the problem at its source. Cyanobacteria are one of the main producers of these compounds in freshwater ecosystems. In this study, we analyzed 13 samples (9 cyanobacteria cultures from Bafa Lake, Elmalı Dam Lake, İznik Lake, Küçükçekmece Lake, Manyas Lake and Taşkısığı Lake, and 4 environmental water samples from Erfelek and Günpınar Waterfalls and Ömerli Dam Lake) for GEO and MIB production by HS-SPME (Head space-solid phase microextraction) coupled with GC-MS (gas chromatography-mass spectrometry). The presence of Cyanobacteria-specific GEO and MIB synthase genes were also analyzed by PCR (Polymerase Chain Reaction). Taste and odour production was confirmed in 2 samples by GC-MS while 4 samples yielded positive results by PCR. All positive samples were environmental samples (3 samples from waterfalls from Günpınar and Erfelek Waterfalls, 1 sample from Ömerli Dam Lake -a drinking water reservoir) which were dominated by Nostoc Vaucher ex Bornet amp; Flahault, Phormidium Kützing ex Gomont and Pseudanabaena Lauterborn. This is the first report of GEO and MIB producing cyanobacteria in Turkish freshwaters by combining microscopy, analytical and molecular techniques.

Keywords

• geosmin
• 2-methylisoborneol
• taste and odour
• cyanobacteria
• pcr
• gc-ms