Centre for Marine and Environmental Research, CIMA, Faculty of Sciences and Technology, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal.
J Ind Microbiol Biotechnol. 2010 Nov;37(11):1145-55. doi: 10.1007/s10295-010-0762-1. Epub 2010 Jul 1.
Large-scale production has been the major obstacle to the success of many biopesticides. The spreading of microbial biocontrol agents against postharvest disease, as a safe and environmentally friendly alternative to synthetic fungicides, is quite dependent on their industrial mass production from low-cost raw materials. Considerable interest has been shown in using agricultural waste products and by-products from food industry as nitrogen and carbon sources. In this work, carob pulp aqueous extracts were used as carbon source in the production of the biocontrol agent Pantoea agglomerans PBC-1. Optimal sugar extraction was achieved at a solid/liquid ratio of 1:10 (w/v), at 25°C, for 1 h. Batch experiments were performed in shake flasks, at different concentrations and in stirred reactors at two initial inoculums concentrations, 10(6) and 10(7) cfu ml(-1). The initial sugar concentration of 5 g l(-1) allowed rapid growth (0.16 h(-1)) and high biomass productivity (0.28 g l(-1) h(-1)) and was chosen as the value for use in stirred reactor experiments. After 22 and 32 h of fermentation the viable population reached was 3.2 × 10(9) and 6.2 × 10(9) cfu ml(-1) in the fermenter inoculated at 10(6) cfu ml(-1) and 2.7 × 10(9) and 6.7 × 10(9) cfu ml(-1) in the bioreactor inoculated at 10(7) cfu ml(-1). A 78% reduction of the pathogen incidence was achieved with PBC-1 at 1 × 10(8) cfu ml(-1), grown in medium with carob extracts, on artificially wounded apples stored after 7 days at 25°C against P. expansum.
大规模生产一直是许多生物农药成功的主要障碍。微生物生防剂对采后病害的防治作为合成杀菌剂的安全和环保替代品，其工业大规模生产非常依赖于从低成本原料中进行。人们对利用农业废弃物和食品工业的副产物作为氮源和碳源产生了极大的兴趣。在这项工作中，角豆 pulp 水提物被用作生防剂 Pantoea agglomerans PBC-1 的碳源。在固液比为 1:10（w/v）、25°C、1 h 的条件下，实现了最佳的糖提取。在不同浓度的摇瓶和两个初始接种浓度（10(6)和 10(7)cfu ml(-1))的搅拌反应器中进行了分批实验。初始糖浓度为 5 g l(-1)可实现快速生长（0.16 h(-1)）和高生物量生产率（0.28 g l(-1) h(-1)），因此选择该浓度用于搅拌反应器实验。在发酵器中接种 10(6)cfu ml(-1)和 10(7)cfu ml(-1)时，发酵 22 和 32 h 后，活菌数分别达到 3.2×10(9)和 6.2×10(9)cfu ml(-1)和 2.7×10(9)和 6.7×10(9)cfu ml(-1)。用 PBC-1 在含有角豆提取物的培养基中培养至 1×10(8)cfu ml(-1)，可使病原菌发病率降低 78%，接种于 25°C 下贮藏 7 天后的人工刺伤苹果上，可防治 P. expansum。
