Benzo[a]pyrene (B[a]P) is a carcinogenic environmental pollutant widely present in the environment and can enter the human body through the food chain. It is therefore essential to treat and remediate the B[a]P-contaminated environment. Microbial remediation of B[a]P-contaminated environments is considered to be one of the most effective strategies, and the addition of biostimulants is a feasible method to further improve the effectiveness of microbial remediation. In this study, we used MSC4 to screen for the stimulation of sodium gluconate, which promoted B[a]P degradation. Based on biochemical and transcriptomic analyses, Sodium gluconate was found to significantly increase the biomass of MSC4 and the expression of most genes involved in B[a]P degradation. Activities of central carbon metabolism, fatty acid β-oxidation and oxidative phosphorylation were all promoted. The significant increase in acid-induced oxalate decarboxylase expression indicates a decrease in intracellular pH, which promoted the synthesis of acetoin and lactate. Genes involved in the nitrogen cycle, especially nitrification and denitrification, were significantly up-regulated, contributing to B[a]P degradation. Genes involved in the synthesis of enzyme cofactors, including thiamine, molybdenum cofactors, NAD and heme, were up-regulated, which contributes to increasing enzyme activity in metabolic pathways. Up-regulation of genes in flagella assembly, chemotaxis, and lipopeptide synthesis is beneficial for the dissolution and uptake of B[a]P. Genes related to the sugar transport system were upregulated, which facilitates the transport and absorption of monosaccharides and oligosaccharides by MSC4. This study provides a theoretical basis for the further application of sodium gluconate in the treatment of PAH-contaminated sites.

中文翻译：

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葡萄糖酸钠促进枯草芽孢杆菌MSC4降解苯并[a]芘机理的转录组和生化分析

苯并[a]芘（B[a]P）是一种广泛存在于环境中的致癌环境污染物，可通过食物链进入人体。因此，有必要对苯[a]芘污染的环境进行处理和修复。 B[a]P污染环境的微生物修复被认为是最有效的策略之一，而添加生物刺激剂是进一步提高微生物修复效果的可行方法。在本研究中，我们使用 MSC4 筛选葡萄糖酸钠的刺激，从而促进 B[a]P 降解。根据生化和转录组分析，发现葡萄糖酸钠可显着增加 MSC4 的生物量以及大多数参与 B[a]P 降解的基因的表达。中心碳代谢、脂肪酸β-氧化和氧化磷酸化活性均得到促进。酸诱导的草酸脱羧酶表达显着增加表明细胞内pH值降低，从而促进乙偶姻和乳酸的合成。参与氮循环的基因，尤其是硝化和反硝化作用，显着上调，导致 B[a]P 降解。参与酶辅因子（包括硫胺素、钼辅因子、NAD 和血红素）合成的基因上调，这有助于增加代谢途径中酶的活性。鞭毛组装、趋化性和脂肽合成中基因的上调有利于 B[a]P 的溶解和摄取。与糖转运系统相关的基因上调，有利于MSC4对单糖和寡糖的转运和吸收。本研究为葡萄糖酸钠进一步应用于PAH污染场地治理提供理论依据。