Laboratory for Cellulose & Wood Materials, Empa - Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland.
Laboratory for Cellulose & Wood Materials, Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland.
Appl Microbiol Biotechnol. 2023 Feb;107(4):1465-1476. doi: 10.1007/s00253-023-12381-y. Epub 2023 Jan 23.
Trichoderma spp. are ubiquitous soil-borne fungi that are widely used in biological control to promote and regulate healthy plant growth, as well as protect against plant pathogens. However, as with many biological materials, the relative instability of Trichoderma propagules limits its practical use in industrial applications. Therefore, there has been significant research interest in developing novel formulations with various carrier substances that are compatible with these fungal propagules and can enhance the shelf-life and overall efficacy of the Trichoderma. To this end, herein, we investigate the use of a variety of biopolymers and nanoparticles for the stabilization of Trichoderma atrobrunneum T720 conidia for biological control. The best-performing agents-agar and cellulose nanocrystals (CNC)-were then used in the preparation of oil-in-water emulsions to encapsulate conidia of T720. Emulsion properties including oil type, oil:water ratio, and biopolymer/particle concentration were investigated with respect to emulsion stability, droplet size, and viability of T720 conidia over time. Overall, agar-based formulations yielded highly stable emulsions with small droplet sizes, showing no evidence of drastic creaming, or phase separation after 1 month of storage. Moreover, agar-based formulations were able to maintain ~ 100% conidial viability of T720 after 3 months of storage, and over 70% viability after 6 months. We anticipate that the results demonstrated herein will lead to a new generation of significantly improved formulations for practical biological control applications. KEY POINTS: • Various biopolymers were evaluated for improving the stability of Trichoderma conidia • Oil in water emulsions was prepared using cellulose nanocrystals and agar as interface stabilizers • Agar-based emulsions showed ~ 100% viability for encapsulated conidia after 3 months of storage.
木霉属真菌是普遍存在于土壤中的真菌，广泛应用于生物防治，以促进和调节健康植物的生长，并防止植物病原体的侵害。然而，与许多生物材料一样，木霉属分生孢子的相对不稳定性限制了其在工业应用中的实际使用。因此，人们对开发各种载体物质的新型配方产生了浓厚的兴趣，这些载体物质与这些真菌分生孢子相容，并能提高木霉属分生孢子的保质期和整体功效。为此，本文研究了使用各种生物聚合物和纳米粒子来稳定木霉属（Atrobrunneum）T720 分生孢子，以进行生物防治。然后，在制备油包水乳液时，使用性能最佳的两种试剂——琼脂和纤维素纳米晶体（CNC）来包封 T720 分生孢子。考察了乳液性质，包括油的类型、油：水比以及生物聚合物/颗粒浓度，以研究乳液稳定性、液滴大小以及 T720 分生孢子随时间的活力。总体而言，基于琼脂的配方产生了高度稳定的乳液，其液滴尺寸较小，在储存 1 个月后没有明显的分层或相分离的迹象。此外，基于琼脂的配方能够在储存 3 个月后保持 T720 分生孢子的活力约为 100%，在储存 6 个月后仍保持 70%以上的活力。我们预计，本文所展示的结果将为实际生物防治应用带来新一代显著改进的配方。关键点：• 评估了各种生物聚合物以提高木霉属分生孢子的稳定性。• 使用纤维素纳米晶体和琼脂作为界面稳定剂制备水包油乳液。• 基于琼脂的乳液在储存 3 个月后，包封的分生孢子活力约为 100%。
