我们研究了各种复杂的有机氮源对球孢白僵菌深层液体发酵的影响,一种通用的昆虫病原真菌,以产生亲水性酵母样单细胞而闻名,称为胚孢子。具体来说,我们检查了酵母提取物,自溶酵母,无活性酵母,棉籽粉,玉米麸皮,和玉米麸质粉作为具有不同碳氮比(C:N)的氮化合物。我们的综合分析包括芽孢子生产,对非生物胁迫的耐受性,干燥后的货架稳定性,和对粉虫幼虫的毒力,开发有效的基于芽孢子的生物农药的关键属性。值得注意的是,棉籽粉成为最佳氮源,在生物反应器中3天内产生高达2.5×109个小孢子/mL。这些芽孢子对热应力和UV-B辐射暴露表现出最高的耐受性。胚芽孢子组成中的内源C:N比也受到氮源的影响。对粉虫幼虫的生物测定表明,来自棉籽粉的小孢子是最具毒性的,实现更快的致死率(较低的LT50)和需要较低的接种物(LC50)。重要的是,用棉籽粉产生的小孢子在储存过程中表现出延长的活力,与在4°C下180天的自溶酵母相比,超过了生存力的保留。尽管储存可行性存在差异,两种氮源都对粉虫具有相似的长期胚芽孢子生物活性。总之,这项研究促进了我们对复杂有机氮选择对芽孢子的表型性状与其细胞内C:N比相关的关键影响的理解,有助于生态健康的生产,货架稳定,和强毒繁殖体,用于有效的害虫生物防治计划。
目的:通过昆虫病原真菌进行生物防治为农业害虫的综合管理提供了必要的生态服务。在液体深层发酵的背景下,营养成分显著影响生态适应性,这些真菌的毒力和质量。这项研究专门探讨了来自农业工业副产品的各种复杂有机氮源对球孢白僵菌深层液体发酵的影响,一种多才多艺的昆虫病原真菌,以产生亲水性酵母样孢子而闻名。值得注意的是,在深层培养过程中操纵氮源会影响质量,健身,和芽胞孢子的表现。这项研究确定棉籽粉是最佳的低成本氮源,有助于增加产量,增强的多应力耐受性,增强的毒力,延长的保质期和长期的生物活性。这些发现加深了我们对氮化合物选择在液体培养基配方中的关键作用的理解。促进生态上适合和毒性小孢子的生产,以实现更有效的害虫生物防治计划。
We investigated the impact of various complex organic nitrogen sources on the submerged liquid fermentation of Beauveria bassiana, a versatile entomopathogenic fungus known for producing hydrophilic yeast-like single cells called blastospores. Specifically, we examined yeast extract, autolyzed yeast, inactive yeast, cottonseed flour, corn bran, and corn gluten meal as nitrogen compounds with different carbon-to-nitrogen (C:N) ratios. Our comprehensive analysis encompassed blastospore production, tolerance to abiotic stresses, shelf stability after drying, and virulence against mealworm larvae, crucial attributes for developing effective blastospore-based biopesticides. Notably, cottonseed flour emerged as the optimal nitrogen source, yielding up to 2.5 × 109 blastospores/mL within 3 days in a bioreactor. These blastospores exhibited the highest tolerance to heat stress and UV-B radiation exposure. The endogenous C:N ratio in blastospore composition was also impacted by nitrogen sources. Bioassays with mealworm larvae demonstrated that blastospores from cottonseed flour were the most virulent, achieving faster lethality (lower LT50) and requiring a lower inoculum (LC50). Importantly, blastospores produced with cottonseed flour displayed extended viability during storage, surpassing the retention of viability compared to those from autolyzed yeast over 180 days at 4°C. Despite differences in storage viability, both nitrogen sources conferred similar long-term blastospore bioactivity against mealworms. In summary, this research advances our understanding of the crucial impact of complex organic nitrogen selection on the phenotypic traits of blastospores in association with their intracellular C:N ratio, contributing to the production of ecologically fit, shelf-stable, and virulent propagules for effective pest biocontrol programs.
OBJECTIVE: Biological control through entomopathogenic fungi provides essential ecological services in the integrated management of agricultural pests. In the context of submerged liquid fermentation, the nutritional composition significantly influences the ecological fitness, virulence and quality of these fungi. This study specifically explores the impact of various complex organic nitrogen sources derived from agro-industrial byproducts on the submerged liquid fermentation of Beauveria bassiana, a versatile entomopathogenic fungus known for producing hydrophilic yeast-like blastospores. Notably, manipulating the nitrogen source during submerged cultivation can influence the quality, fitness, and performance of blastospores. This research identifies cottonseed flour as the optimal low-cost nitrogen source, contributing to increased production yields, enhanced multi-stress tolerance, heightened virulence with extended shelf life and long-term bioactivity. These findings deepen our understanding of the critical role of nitrogen compound selection in liquid media formulation, facilitating the production of ecologically fit and virulent blastospores for more effective pest biocontrol programs.