Page 161 - 2025中醫藥與天然藥物聯合學術研討會-中醫藥與天然藥物的挑戰Ｘ機遇與未來大會手冊

PC-43

From rice cultivation to uncommon metabolites: solid-state fermentation

unlocks cryptic metabolic potential of Aspergillus westerdijkiae

,2
Bertoka Fajar Surya Perwira Negara, #,1 Yuan-Bin Cheng*

1 International Doctoral Program of Marine Science and Technology, National Sun Yat-sen
University, Kaohsiung 804201, Taiwan
2 Department of Marine Biotechnology and Resources, National Sun Yat-sen University,
Kaohsiung 804201, Taiwan
* E-mail: jmb@mail.nsysu.edu.tw

Abstract
In recent years, filamentous fungi have been uncovered as a new resource for drug lead
compounds. Among these, Aspergillus westerdijkiae has shown great promise as a producer of
bioactive compounds. Previous research reported that A. westerdijkiae is known to produce
compounds such as asperloxins, ochratoxins (A and B), circumdatins (A–G), and melein. This
study aimed to investigate the cryptic secondary metabolic of A. westerdijkiae through solid-
state fermentation. A. westerdijkiae was isolated from Cespitularia hypotentaculata and
fermented using rice through solid-state fermentation for 20 days. Fermented culture was
extracted by using ethyl acetate and partitioned using 75% MeOH and hexanes in a ratio of 1:1.
The 75% MeOH layer was then subjected to chromatographic fractionation. The fractionation
enabled the isolation of five known compounds with diverse structural scaffolds. These
compounds were one pyrrolidinedione alkaloid: (+)-preussin (1), two dihydroisocoumarins:
mellein (2) and 7-hydroxymellein (3); and two diketopiperazines: circumdatin F (4) and
circumdatin G (5). Structural elucidation was done by using NMR (1D and 2D), mass
spectrometry, and optical rotation analyses. It is worth mentioning that this is the first confirmed
report of (+)-preussin that was isolated from A. westerdijkiae. These findings highlight the
potential of solid-state fermentation as an effective strategy for discovering cryptic secondary
metabolites from fungal sources.

Keywords: Aspergillus westerdijkiae; Solid-state fermentation; Metabolites; cryptic