Thermophilic and non-thermophilic Campylobacter species Emits Distinct Volatile Organic Compounds in Different Culture Media and Growth Phases

Bacteria emits a multitude of volatile organic compounds (VOCs) into the headspace as a mean of interactions with the environments, as well as intra- and interkingdom communication for survival and persistence in the nature and within their hosts. Campylobacter, which is often found in poultry and ruminants, has shown great persistence in aquatic environments, making it one of the world's most dangerous foodborne pathogens, killing thousands of people annually. In this study, the VOCs emitted by both thermophilic (C. jejuni, C. coli and C. lari) and non-thermophilic Campylobacter (C. fetus) of clinical concerns, impacted by nutrients composition (media) and growth phase were identified. Most thermophilic Campylobacter were shown to release volatile alcohols and ketones (1s,4R,7R,11R-1,3,4,7-Tetramethyltricyclo [5.3.1.0(4,11)] undec-2-en-8-one and Isophorone) during early stationary and stationary phases using active sampling with active charcoal adsorbent and GC-MS analysis. C. jejuni cultured in the Brain Heart Infusion had 1-Heptadecanol in its headspace gas, but not in Bolton Broth. The non-thermophilic C. fetus did not produce alcohols or ketones, but rather a variety of unidentified chemicals that will require further investigation in the future. Overall, PCA analysis revealed that the five Campylobacter strains studied created distinct volatilomes, allowing for future Campylobacter identification based on VOCs.

Development of ball surface acoustic wave gas chromatograph for environmental monitoring in spacecraft and its application on the ground

For on-site analysis of surface materials on the moon, planets, and small bodies and for the monitoring of air quality in crewed spacecraft, we have developed a portable gas chromatograph (GC) equipped with a ball surface acoustic wave (SAW) sensor. In this study, we fabricated a 10 cm cube GC that implements the forward flush method using two metal micro-electro-mechanical-system (MEMS) columns coated with different stationary phases in microchannels fabricated by wet etching and diffusion bonding of stainless-steel plates. Using this GC, we succeeded in analyzing 10 kinds of gas within 10 min. In addition, for the application of the ball SAW GC on the ground, we also developed a palm-sized GC with a single metal capillary column and used it in the analysis of the headspace gas of sake. We showed that the ratio of peak areas differed among odorants depending on the brand and brewing process of sake.

Stationary Phases for Green Liquid Chromatography

Industrial research, including pharmaceutical research, is increasingly using liquid chromatography techniques. This involves the production of large quantities of hazardous and toxic organic waste. Therefore, it is essential at this point to focus interest on solutions proposed by so-called “green chemistry”. One such solution is the search for new methods or the use of new materials that will reduce waste. One of the most promising ideas is to perform chromatographic separation using pure water, without organic solvents, as a mobile phase. Such an approach requires novel stationary phases or specific chromatographic conditions, such as an elevated separation temperature. The following review paper aims to gather information on stationary phases used for separation under purely aqueous conditions at various temperatures.