WG Fermentation and Formulation of Biologicals and Chemicals, Faculty of Engineering and Mathematics, Bielefeld University of Applied Sciences, Bielefeld, Germany.
Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Bielefeld, Germany.
World J Microbiol Biotechnol. 2018 Jul 3;34(8):108. doi: 10.1007/s11274-018-2492-x.
Successful commercialization of microbial biocontrol agents, such as Metarhizium spp., is often constrained by poor drying survival and shelf life. Here, we hypothesized that culture age would influence endogenous arabitol, erythritol, mannitol and trehalose contents in M. brunneum mycelium and that elevated levels of these compounds would improve drying survival and shelf life of encapsulated mycelium coupled with enhanced fungal virulence against T. molitor larvae. We found that culture age significantly influenced endogenous arabitol and mannitol contents in mycelium with highest concentrations of 0.6 ± 0.2 and 2.1 ± 0.2 µg/mg after 72 h, respectively. Drying survival of encapsulated mycelium was independent of culture age and polyol content with 41.1 ± 4.4 to 55.0 ± 6.2%. Best shelf life was determined for biomass harvested after 72 h at all investigated storage temperatures with maximum values of 59.5 ± 3.3% at 5 °C followed by 54.5 ± 1.6% at 18 °C and 19.4 ± 1.3% at 25 °C after 6 months. Finally, high fungal virulence against T. molitor larvae of 83.3 ± 7.6 to 98.0 ± 1.8% was maintained during storage of encapsulated mycelium for 12 months with larval mortalities being independent of culture age and polyol content. In conclusion, our findings indicate beneficial effects of endogenous polyols in improving shelf life of encapsulated mycelium and this may spur the successful development of microbial biocontrol agents in the future.
微生物生物防治剂（如绿僵菌）的商业化通常受到干燥存活率和保质期差的限制。在这里，我们假设培养年龄会影响 M. brunneum 菌丝体中的内源性阿拉伯糖醇、赤藓糖醇、甘露醇和海藻糖含量，并且这些化合物含量的提高会改善包封菌丝体的干燥存活率和保质期，同时增强真菌对 T. molitor 幼虫的毒力。我们发现培养年龄显著影响菌丝体中的内源性阿拉伯糖醇和甘露醇含量，分别在 72 小时后达到最高浓度 0.6±0.2 和 2.1±0.2µg/mg。包封菌丝体的干燥存活率与培养年龄和多元醇含量无关，为 41.1±4.4 至 55.0±6.2%。在所有研究的储存温度下，72 小时收获的生物量的保质期最佳，在 5°C 时达到最大值 59.5±3.3%，在 18°C 时为 54.5±1.6%，在 25°C 时为 19.4±1.3%，在 6 个月后。最后，在包封菌丝体储存 12 个月期间，对 T. molitor 幼虫的高真菌毒力保持在 83.3±7.6 至 98.0±1.8%，幼虫死亡率与培养年龄和多元醇含量无关。总之，我们的研究结果表明内源性多元醇在提高包封菌丝体保质期方面具有有益的作用，这可能会促进未来微生物生物防治剂的成功开发。
