Encapsulation of Bacillus thuringiensis in an inverse Pickering emulsion for pest control applications

Noga Yaakov; Chandrasekhar Kottakota; Karthik Ananth Mani; Shoham Matsrafi Naftali; Einat Zelinger; Michael Davidovitz; Dana Ment; Guy Mechrez

doi:10.1016/j.colsurfb.2022.112427

Encapsulation of Bacillus thuringiensis in an inverse Pickering emulsion for pest control applications

Colloids Surf B Biointerfaces. 2022 May:213:112427. doi: 10.1016/j.colsurfb.2022.112427. Epub 2022 Feb 24.

Authors

Noga Yaakov¹, Chandrasekhar Kottakota², Karthik Ananth Mani³, Shoham Matsrafi Naftali³, Einat Zelinger⁴, Michael Davidovitz⁵, Dana Ment⁶, Guy Mechrez⁷

Affiliations

¹ Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel.
² Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel; Department of Biochemistry and Biotechnology, Sri Krishnadevaraya College of Agricultural Sciences (SKCAS), Anantapurum, Andhra Pradesh, 515002, Affiliated to Acharya N.G. Ranga Agricultural University (ANGRAU), Guntur, Andhra Pradesh 522034, India.
³ Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel; Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 7610001, Israel.
⁴ The Interdepartmental Equipment Unit, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 7610001, Israel.
⁵ Department of Entomology, Institute of Plant Protection, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel.
⁶ Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel.
⁷ Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel. Electronic address: guyme@agri.gov.il.

PMID: 35219966
DOI: 10.1016/j.colsurfb.2022.112427

Abstract

Here, we present an inverse Pickering emulsion-based formulation for Bacillus thuringiensis serovar aizawai (BtA) encapsulations utilized towards pest control applications. The emulsification was carried out by high shear homogenization process via ULTRA-TURRAX®. The water-in-mineral oil emulsions were stabilized by commercial hydrophobic silica. Different silica contents and water/oil ratios were studied. Stable emulsions were obtained at 2 and 3 wt% silica at 30% and 20% water volumes, respectively. The structure of the Pickering emulsions were characterized by laser scanning confocal microscopy and cryogenic scanning electron microscopy. The BtA cells, spores and crystals were encapsulated in the water droplets of the inverse Pickering emulsions. An emulsion composed of 3 wt% silica and 30% water was found to be the most suitable for encapsulation. The pest control efficiency of the encapsulated BtA against Spodoptera littoralis first instar larvae was tested. The studied BtA/emulsion system exhibited a mortality rate of 92%. However, the non-formulated BtA has shown 71% mortality, and the emulsion alone resulted in only 9% mortality. These findings confirm that an emulsion with encapsulated BtA can function as an efficient formulation for biopesticides.

Keywords: Bacillus thuringien serovar aizawai; Crystal; Encapsulation; Microbial control; Pickering emulsion; Silica; Spodoptera littoralis; Spore; Water-in-oil.

MeSH terms

Bacillus thuringiensis*
Emulsions / chemistry
Pest Control
Silicon Dioxide
Water / chemistry

Substances

Emulsions
Water
Silicon Dioxide