Pectinaceous agricultural residues rich in D-galacturonic acid (D-GalA), such as sugar beet pulp, are considered as promising feedstocks for waste-to-value conversions. Aspergillus niger is known for its strong pectinolytic activity. However, while specialized strains for production of citric acid or proteins are well characterized, this is not the case for the production of pectinases. We, therefore, systematically compared the pectinolytic capabilities of six A. niger strains (ATCC 1015, ATCC 11414, NRRL 3122, CBS 513.88, NRRL 3, and N402) using controlled batch cultivations in stirred-tank bioreactors. A. niger ATCC 11414 showed the highest polygalacturonase activity, specific protein secretion, and a suitable morphology. Furthermore, D-GalA release from sugar beet pulp was 75% higher compared to the standard lab strain A. niger N402. Our study, therefore, presents a robust initial strain selection to guide future process improvement of D-GalA production from agricultural residues and identifies a high-performance base strain for further genetic optimizations.

中文翻译：

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黑曲霉菌株的内源性果胶解聚能力和D-半乳糖醛酸生产适用性的比较评估。

甜菜粕等富含D-半乳糖醛酸（D-GalA）的果胶农业残留物被认为是有前途的原料，可用于废物向价值的转化。黑曲霉因其强大的果胶分解活性而闻名。然而，尽管已经很好地表征了用于生产柠檬酸或蛋白质的专用菌株，但是对于果胶酶的生产却并非如此。因此，我们使用搅拌罐式生物反应器中的受控分批培养系统地比较了六个黑曲霉菌株（ATCC 1015，ATCC 11414，NRRL 3122，CBS 513.88，NRRL 3和N402）的果胶溶解能力。黑曲霉ATCC 11414显示出最高的半乳糖醛酸酶活性，特定的蛋白质分泌和合适的形态。此外，与标准实验室菌株黑曲霉N402相比，甜菜果肉中的D-GalA释放量高75％。我们的研究