Affiliations 

  • 1 Department of Chemical and Environmental Engineering, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia (UTM)
  • 2 Graduate School of Life and Environmental Science, University of Tsukuba
  • 3 Department of Mechanical Precision Engineering, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia (UTM)
J Gen Appl Microbiol, 2021 Jul 31;67(3):92-99.
PMID: 33642451 DOI: 10.2323/jgam.2020.08.001

Abstract

Musty odor production by actinomycetes is usually related to the presence of geosmin and 2-methylisoborneol (2-MIB), which are synthesized by enzymes encoded by the geoA and tpc genes, respectively. Streptomyces spp. strain S10, which was isolated from a water reservoir in Malaysia, has the ability to produce geosmin when cultivated in a basal salt (BS) solid medium, but no 2-MIB production occurred during growth in BS medium. Strain S10 could produce higher levels of geosmin when the phosphate concentration was limited to 0.05 mg/L, with a yield of 17.53 ± 3.12 ✕ 105 ng/L, compared with growth in BS medium. Interestingly, 2-MIB production was suddenly detected when the nitrate concentration was limited to 1.0 mg/L, with a yield of 1.4 ± 0.11 ✕ 105 ng/L. Therefore, it was concluded that phosphate- and nitrate-limiting conditions could induce the initial production of geosmin and 2-MIB by strain S10. Furthermore, a positive amplicon of geoA was detected in strain S10, but no tpc amplicon was detected by PCR analysis. Draft genome sequence analysis showed that one open reading frame (ORF) contained a conserved motif of geosmin synthase with 95% identity with geoA in Streptomyces coelicolor A3 (2). In the case of the tpc genes, it was found that one ORF showed 23% identity to the known tpc gene in S. coelicolor A3(2), but strain S10 lacked one motif in the N-terminus.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.