Monitoring growth promotion of Clostridium Tetani using head space solid-phase microextraction (SPME) coupled to GC-MS

HS-SPME-GC-MS method, allows determination of biogenic volatile organic compounds (BVOCs) emerged from microorganism, thus provides a new, simple, and reliable tool for studying the growth promotion of microorganisms in growth phases [1,2]. This is an adaptable analytical method which employed to prepare a comprehensive chemical profile of volatile compounds emitted from microorganisms in different environments. In this study sol-gel based SPME fibers were applied for extraction of VOCs, emerged from Clostridium Tetani in different media, followed by GC-MS analysis. About fifty components were identified by proposed method. The main detected compounds were sulfur compounds such as Butanethioic acid S-methyl ester, dimethyl trisulfide, and dimethyl tetrasulfide which could be used as a biomarker for monitoring bacterial growth in bioreactor. In second step, portable dynamic air sampling (PDAS) device was constructed and used for extraction of VOCs from exhaust gas flow of bioreactor. The influencing parameters were investigated and optimized.At optimized condition. the exhaust gas flow rate was 1mLS-1 and retention time of SPME fiber in PDAS was 20 minutes. Sampling procedure repeated 6 times per day during incubation period. Other parameters such as pH, optical density were measured during the sampling time. A Limit of flocculation (LF) result of 70 LfmL-1was obtained by monitoring the biomarkers which higher than LF resulted in conventional monitoring parameters.