M Zareian1, P Silcock1, P Bremer1. 1. Department of Food Science, University of Otago, Dunedin, New Zealand.
Abstract
AIMS: To monitor temporal changes in the volatile organic compounds' (VOCs) profile generated by the metabolic activities of Pseudomonads in real time. METHODS AND RESULTS: Three Pseudomonas strains were cultivated in Vogel's broth, supplemented with glucose (0·5 or 1%) and/or protein (egg white powder at 0 or 2%) at 25°C. Glucose or egg white protein contents influenced the VOCs' release profile for alcohols, carbonyls and sulphur derivatives. Increasing glucose content resulted in higher alcohol and ketone contents. Glucose showed a lower effect on the VOCs' release profile, mainly impacting on individual compounds, such as m/z 89 (3-methyl-1-butanol). In contrast, egg white protein enhanced production of VOCs such as m/z 75 (2-methyl-1-propanol) and m/z 63 (dimethyl sulphide) regardless of glucose level present in the medium. At the end of bacteria growth phase (54, 60 and 72 h), the fingerprint of VOCs was different from the early growth phase. Cells near to the end of their growth phase (54, 60 and 72 h) produced a distinctly different array of compounds compared to those produced in early growth phase, for example, cyclic compounds were detected in early growth phase, whereas sulphur derivatives were more common in late growth phase. CONCLUSIONS: Pseudomonads-mediated VOCs' fingerprint as a response to varying growth conditions can be identified as latent biomarkers. SIGNIFICANCE AND IMPACT OF THE STUDY: Understanding how microbially mediated VOCs' release profile responds to varying growth conditions can potentially be used as a rapid method for detecting microbial activities in controlled conditions such as food quality systems.
AIMS: To monitor temporal changes in the volatile organic compounds' (VOCs) profile generated by the metabolic activities of Pseudomonads in real time. METHODS AND RESULTS: Three Pseudomonas strains were cultivated in Vogel's broth, supplemented with glucose (0·5 or 1%) and/or protein (egg white powder at 0 or 2%) at 25°C. Glucose or egg white protein contents influenced the VOCs' release profile for alcohols, carbonyls and sulphur derivatives. Increasing glucose content resulted in higher alcohol and ketone contents. Glucose showed a lower effect on the VOCs' release profile, mainly impacting on individual compounds, such as m/z 89 (3-methyl-1-butanol). In contrast, egg white protein enhanced production of VOCs such as m/z 75 (2-methyl-1-propanol) and m/z 63 (dimethyl sulphide) regardless of glucose level present in the medium. At the end of bacteria growth phase (54, 60 and 72 h), the fingerprint of VOCs was different from the early growth phase. Cells near to the end of their growth phase (54, 60 and 72 h) produced a distinctly different array of compounds compared to those produced in early growth phase, for example, cyclic compounds were detected in early growth phase, whereas sulphur derivatives were more common in late growth phase. CONCLUSIONS: Pseudomonads-mediated VOCs' fingerprint as a response to varying growth conditions can be identified as latent biomarkers. SIGNIFICANCE AND IMPACT OF THE STUDY: Understanding how microbially mediated VOCs' release profile responds to varying growth conditions can potentially be used as a rapid method for detecting microbial activities in controlled conditions such as food quality systems.
Authors: Keith Hewett; Natalia Drabińska; Paul White; Matthew B Avison; Raj Persad; Norman Ratcliffe; Ben de Lacy Costello Journal: Antibiotics (Basel) Date: 2020-11-11
Authors: Xiaogang Li; Paolina Garbeva; Xiaojiao Liu; Paulien J A Klein Gunnewiek; Anna Clocchiatti; Maria P J Hundscheid; Xingxiang Wang; Wietse de Boer Journal: Environ Microbiol Date: 2019-11-04 Impact factor: 5.491