Identification of microorganisms involved in the formation of styrene in Cinnamomum zeylanicum powder.

Abstract

Sri Lanka is the world's largest producer of the highest quality cinnamon quills, with distinct grades such as Alba, Continental (C grade), Mexican (M grade), and Hamburg (H grade). The cinnamon production process involves harvesting, processing, drying, grading, and potential cutting or grinding for the final product, often in powder form. The principal compound in cinnamon bark is trans-cinnamaldehyde. A malodorous compound, identified as styrene through GC-MS analysis, is formed with cinnamon powder over time due to microbial activity. This study focuses on identifying the microbes responsible for styrene production in cinnamon powder. Two samples of cinnamon machine powder categorized as old and fresh, were used for the analysis. Potential microorganisms from both samples were allowed to be grown on Potato Dextrose Agar (PDA) (with Chloramphenicol) and Luria Berta (LB) (with Amphotericin B) plates and their macro and micro-morphological characteristics were observed. In the old cinnamon machine powder sample five fungal species were isolated, while the fresh sample yielded one fungal species. Notably, one colony from old and fresh cinnamon powder samples exhibited both fungal and bacterial characteristics. Genomic DNA extracted, using the GES method, amplified a 550 bp PCR product for the ITS region, while no specific single band was obtained for the 16S rRNA gene suggesting that the unknown species is likely fungal. The morphological identification indicated characteristics of Aspergillus species when grown on PDA medium. This research revealed the possible existence of a microbial consortium with fungal characteristics. Further studies on microbial composition of cinnamon machine powder and its potential link to the formation of styrene may contribute valuable insights for quality control in the cinnamon industry.