Background The development of biorefinery systems that use lignocellulosic biomass as a renewable carbon source to produce fuels and chemicals is attracting increasing attention. The process cost of enzymatic saccharification of biomass is a major challenge for commercialization. To decrease this cost, researchers have proposed on-site solid-state fermentation (SSF). This study investigated the feasibility of using Aspergillus oryzae as a host microorganism for SSF recombinant enzyme production with ammonia-treated rice straw as model biomass. Eight A. oryzae strains were tested, all of which are used in the food industry. We evaluated the effects of acetic acid, a fermentation inhibitor. We also developed a platform strain for targeted recombinant enzyme production by gene engineering technologies. Results The SSF validation test showed variation in the visibility of mycelium growth and secreted protein in all eight A. oryzae strains. The strains used to produce shoyu and miso grew better under test conditions. The ammonia-treated rice straw contained noticeable amounts of acetic acid. This acetic acid enhanced the protein production by A. oryzae in a liquid-state fermentation test. The newly developed platform strain successfully secreted three foreign saccharifying enzymes. Conclusions A. oryzae is a promising candidate as a host microorganism for on-site SSF recombinant enzyme production, which bodes well for the future development of a more cost-efficient saccharifying enzyme production system.

中文翻译：

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米曲霉现场生产固态酶的可行性研究。

背景使用木质纤维素生物质作为可再生碳源来生产燃料和化学品的生物精炼系统的开发正引起越来越多的关注。生物质酶糖化的工艺成本是商业化的主要挑战。为了降低成本，研究人员提出了现场固态发酵 (SSF)。本研究调查了以米曲霉为宿主微生物，以氨处理稻草为模型生物质生产 SSF 重组酶的可行性。测试了八种米曲霉菌株，所有这些菌株都用于食品工业。我们评估了乙酸（一种发酵抑制剂）的作用。我们还开发了一种平台菌株，用于通过基因工程技术进行靶向重组酶生产。结果 SSF 验证测试显示所有八种米曲霉菌株的菌丝体生长和分泌蛋白的可见度存在差异。用于生产酱油和味噌的菌株在测试条件下生长得更好。氨处理过的稻草含有大量的乙酸。在液态发酵试验中，这种乙酸提高了米曲霉的蛋白质产量。新开发的平台菌株成功分泌了三种外源糖化酶。结论 A. oryzae 作为现场 SSF 重组酶生产的宿主微生物是有前景的候选者，这预示着未来开发更具成本效益的糖化酶生产系统。用于生产酱油和味噌的菌株在测试条件下生长得更好。氨处理过的稻草含有大量的乙酸。在液态发酵试验中，这种乙酸提高了米曲霉的蛋白质产量。新开发的平台菌株成功分泌了三种外源糖化酶。结论 A. oryzae 作为现场 SSF 重组酶生产的宿主微生物是有前景的候选者，这预示着未来开发更具成本效益的糖化酶生产系统。用于生产酱油和味噌的菌株在测试条件下生长得更好。氨处理过的稻草含有大量的乙酸。在液态发酵试验中，这种乙酸提高了米曲霉的蛋白质产量。新开发的平台菌株成功分泌了三种外源糖化酶。结论 A. oryzae 作为现场 SSF 重组酶生产的宿主微生物是有前景的候选者，这预示着未来开发更具成本效益的糖化酶生产系统。新开发的平台菌株成功分泌了三种外源糖化酶。结论 A. oryzae 作为现场 SSF 重组酶生产的宿主微生物是很有前景的候选者，这预示着未来开发更具成本效益的糖化酶生产系统。新开发的平台菌株成功分泌了三种外源糖化酶。结论 A. oryzae 作为现场 SSF 重组酶生产的宿主微生物是很有前景的候选者，这预示着未来开发更具成本效益的糖化酶生产系统。