Open Access

ARTICLE

Controlled-Release of Plant Volatiles: New Composite Materials of Porous Carbon-Citral and Their Fungicidal Activity against Exobasidium vexans

by Yaoguo Liu¹, Yao Chen², Huifang Liu², Wei Chen¹, Zhiwei Lei², Chiyu Ma², Jie Yin¹, Wen Yang^2,*

1 College of Tea Science, Guizhou University, Guiyang, 550025, China
2 Guizhou Tea Research Institute, Guizhou Academy of Agricultural Sciences, Guiyang, 550006, China

* Corresponding Author: Wen Yang. Email:

(This article belongs to the Special Issue: Porous Materials for Sustainable Development)

Journal of Renewable Materials 2023, 11(2), 811-823. https://doi.org/10.32604/jrm.2022.022594

Received 16 March 2022; Accepted 12 May 2022; Issue published 22 September 2022

Abstract

Citral (Eo) exhibits excellent fungicidal activities. However, it is difficult to maintain long-term fungicidal activity due to its strong volatility. Herein, a controlled-release strategy by using biomass-derived porous carbon (BC) was developed to overcome the drawback of Eo. New composite materials were prepared by loading Eo on tea stem porous carbon (BC@Eo), and their controlled-release fungicidal activity against Exobasidium vexans was assessed. BC with a large specific surface area of 1001.6 m²/g and mesoporous structure was fabricated through carbonization temperature of 700°C. The BC@Eo materials were characterized using Fourier-transform infrared spectroscopy and X-ray powder diffraction. The results suggested that chemical and physical interactions occurred in BC@Eo. The Eo release profile suggested a biphasic pattern with an initial fast release on days 1–14 and a subsequent controlled phase on days 14–30. The in vitro cumulative release percentage of Eo from BC@Eo was 51% during one month, and this result was significantly lower than that from free Eo (cumulative release percentage of Eo of 82% in one week). The antifungal activities of Eo and BC@Eo against E. vexans were determined using the inhibition zone method. The results indicated that Eo and BC@Eo formed large inhibition zones of 19.66 ± 0.79 and 21.92 ± 0.77 mm, respectively. The influence on the hyphal structure of E. vexans was observed by scanning electron microscopy on day 30. The hyphal structure of E. vexans treated with BC@Eo was more shrunken than that treated with Eo at 30 days, suggesting that BC@Eo prolongs the fungicidal activity against E. vexans. This study demonstrated that the encapsulation of Eo in BC for developing the BC@Eo materials could be a promising strategy to inhibit volatility and maintain the fungicidal activity of Eo and provide a potential alternative for the reuse of abundant tea biomass waste resources.

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