Development of biochar-impregnated alginate beads for the delivery of biocontrol agents for peanut aflatoxin

Abstract

The competitive inhibition of aflatoxigenic fungi by non-aflatoxigenic Aspergillus flavus has proved to be an effective method to prevent and control peanut aflatoxin contamination, and most of the currently used inoculum carriers are grains. In this study, the reliability and efficiency of replacing grain kernels with novel chitosan-coated alginate-poly(N-isopropylacrylamide) (PNIPAAm) beads impregnated with biochar (CSACB) were evaluated. Characterisation of the beads was performed by SEM, thermogravimetry analysis (TGA), and swelling properties analyses. The optimised CSACB beads had good physical stability, shelf life, and entrapment efficiency. In addition, the water-holding capacity and porous structure were excellent, as the biochar provided a beneficial microenvironment for the attachment and microbial growth of the biocontrol fungus. The effect of reducing aflatoxin in peanuts was verified experimentally. Collectively, the novel CSACB beads are suitable carriers of non-aflatoxigenic A. flavus for the biocontrol of peanut aflatoxin.

Keywords:

• Alginate
• biochar
• controlled release
• peanut aflatoxin

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Research start-up fund of Jiangsu University of Science and Technology; and Innovation and Entrepreneurship Program of Jiangsu Province.