Sustainable bioenergy based on lignocellulosic biomass needs efficient cellulolytic microbes and enzymes. The present study revealed a thermophilic Bacillus sp. PCH94, a potential cellulolytic bacterium supported by its genomic and functional studies. The genome analysis of strain PCH94 uncovered key cellulolytic enzymes such as endoglucanase, exoglucanase, and β-glucosidase. Bioinformatic tools identified CAZyme gene clusters and unveiled 106 genes for carbohydrate utilization. Molecular characterization revealed a wide temperature (4–80 °C) and pH (4.0–12.0) active cellulolytic enzymes (1.95 IU/mg) produced on damaged rice grain powder. Further, response surface methodology enhanced specific activity by 2.32-fold (4.53 IU/mg). At 10.0 L working volume in a fermenter, the upscale process yielded 1122 U cellulase activity in 9 h at 50 °C. The crude enzyme was tested on a range of substrates such as CMC, filter paper, avicel, xylan, and starch, which confirms the functionality of lignocellulolytic genes encoding enzymes in the genome of Bacillus sp. PCH94. The crude cellulase enzyme showed the highest specific activity of 6.2 IU/mg, which is 4 to 6 times higher than commercial cellulases investigated. Thus, the present study unearths a potential bioresource for efficient cellulase production using damaged rice grain waste, which has future applications in bioethanol, detergent, and textile industries.

Graphic Abstract

中文翻译：

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基因组洞察驱动的喜马拉雅嗜热芽孢杆菌生产高效纤维素酶的统计优化。PCH94 使用农业废弃物

基于木质纤维素生物质的可持续生物能源需要高效的纤维素分解微生物和酶。本研究揭示了一种嗜热芽孢杆菌sp. PCH94，一种由其基因组和功能研究支持的潜在纤维素分解细菌。PCH94 菌株的基因组分析揭示了关键的纤维素分解酶，如内切葡聚糖酶、外切葡聚糖酶和 β-葡糖苷酶。生物信息学工具确定了 CAZyme 基因簇并揭示了 106 个用于碳水化合物利用的基因。分子表征显示，在受损的米粒粉上产生了广泛的温度（4-80°C）和 pH（4.0-12.0）活性纤维素分解酶（1.95 IU/mg）。此外，响应面方法将比活性提高了 2.32 倍（4.53 IU/mg）。在发酵罐中工作体积为 10.0 L 时，高档工艺在 50 °C 下在 9 小时内产生了 1122 U 的纤维素酶活性。粗酶在一系列底物上进行测试，如 CMC、滤纸、微晶纤维素、木聚糖和淀粉，芽孢杆菌属。PCH94。粗纤维素酶的比活性最高，为 6.2 IU/mg，比所研究的商业纤维素酶高 4 至 6 倍。因此，本研究发掘了一种潜在的生物资源，可利用受损的稻谷废料进行高效纤维素酶生产，未来可应用于生物乙醇、洗涤剂和纺织工业。

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