Biogeneration of volatile organic compounds produced by Phormidium autumnale in heterotrophic bioreactor

The objective of this study was to investigate the volatile organic compounds (VOCs) produced from heterotrophic cultivation of the cyanobacterium Phormidium autumnale with different sources of monosaccharides. The volatiles were isolated by headspace solid-phase micro-extraction in different residence times, separated by gas chromatography, and identified by mass spectrometry (SPME-GC/MS). The profile of volatiles contained a total of 44 volatile compounds when P. autumnale was grown heterotrophically on glucose and 35 when grown on fructose. A combined total of 68 compounds was identified and 11 volatiles were common to both extracts. The compound 3-methyl-butanol was identified among the major volatile compounds formed, reaching a concentration of 141.5 mu g mg(-1) dry weight for the glucose-grown cultures and 69.5 mu g mg(-1) for the fructose-grown cultures after 144 h. Many of the compounds detected during heterotrophic cultivation originated from terpenoids (beta-ionone, beta-cyclocitral, and 5,6-epoxy-beta-ionone), fatty acids (hexanol, hexanal), or the 2-keto acid pathway (3-methyl-butanol, propanol, butanol).