Bioactivity assay of Endophytes Colletotrichum siamense strain 67 and Meyerozyma guilliermondii strain CBS 2077 isolated from Stevia rebaudiana (Bertoni) Bertoni and their stevioside glycoside production

• Published in: Biotechnology and bioprocess engineering Vol. 30; no. 4; pp. 733 - 758
• Main Authors: Nishant, Chandra, Sheela
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Society for Biotechnology and Bioengineering 01.08.2025; Springer Nature B.V
• Subjects: Antidiabetics; Antimicrobial activity; Antioxidants; Biological activity; Biotechnology; Chemicals; Chemistry; Chemistry and Materials Science; Chloride; Colletotrichum siamense; Endophytes; Flavonoids; Food industry; Functional foods & nutraceuticals; Fungi; Glycosides; In vivo methods and tests; Industrial and Production Engineering; Leaves; Mass spectrometry; Mass spectroscopy; Metabolites; Meyerozyma guilliermondii; Oxidative stress; Phenolic compounds; Phenols; Plant tissues; Research Paper; Stevia rebaudiana; Stevioside; Syrups & sweeteners; Total flavonoid content; Total phenolic content; Stevioside; 2,2-Diphenylpicrylhydrazyl; Fluorescence recovery after photobleaching; Ultra-high-performance liquid chromatography-electrospray ionization-mass spectrometry
• ISSN: 1226-8372; 1976-3816
• DOI: 10.1007/s12257-025-00201-1

This study highlights the promising potential of endophytic fungi Colletotrichum siamense (SC0T4) and Meyerozyma guilliermondii (SC0T6), isolated from the leaf and root tissues of Stevia rebaudiana (Bertoni) Bertoni, respectively, as alternative sources for stevioside production. Both isolates demonstrated high stevioside yields, with SC0T4 and SC0T6 producing 0.73 mg/mL and 1.07 mg/mL, respectively—significantly higher than concentrations found in in vitro shoots (0.41 mg/g), in vivo leaves (0.52 mg/mL), and other plant-based methods. Mass spectrometry confirmed stevioside-like compounds, with SC0T4 and SC0T6 displaying m/z values of 838.34 and 838.3, compared to the standard 803.4 m/z. Beyond sweetener production, the isolates showed strong bioactive potential. SC0T6 exhibited maximum antimicrobial activity against Pseudomonas aeruginosa (12.6 ± 0.76 mm) and Cladosporium herbarum (23 ± 0.5 mm), while SC0T4 was most effective against Bacillus subtilis (12.6 ± 0.4 mm) and C. herbarum (21 ± 0.4 mm). Additionally, SC0T6 showed high antioxidant activity (48.9 ± 8.33%; 51.1 ± 9.18 µM), and SC0T4 recorded the highest total phenolic (8.31 ± 0.58 µg/g) and flavonoid content (10.1 ± 0.42 µg/g). These findings represent the first report of stevioside glycoside production from these fungal endophytes and support their application as sustainable, eco-friendly alternatives to conventional stevioside sources. Their antimicrobial and antioxidant properties further suggest their potential use in pharmaceutical, nutraceutical, and food industries. Graphical abstract