Alriksson Björn, Rose Shaunita H, van Zyl Willem H, Sjöde Anders, Nilvebrant Nils-Olof, Jönsson Leif J
Department of Chemistry and Biomedical Sciences, Karlstad University, Karlstad, Sweden.
Appl Environ Microbiol. 2009 Apr;75(8):2366-74. doi: 10.1128/AEM.02479-08. Epub 2009 Feb 27.
A recombinant Aspergillus niger strain expressing the Hypocrea jecorina endoglucanase Cel7B was grown on spent hydrolysates (stillage) from sugarcane bagasse and spruce wood. The spent hydrolysates served as excellent growth media for the Cel7B-producing strain, A. niger D15[egI], which displayed higher endoglucanase activities in the spent hydrolysates than in standard medium with a comparable monosaccharide content (e.g., 2,100 nkat/ml in spent bagasse hydrolysate compared to 480 nkat/ml in standard glucose-based medium). In addition, A. niger D15[egI] was also able to consume or convert other lignocellulose-derived compounds, such as acetic acid, furan aldehydes, and phenolic compounds, which are recognized as inhibitors of yeast during ethanolic fermentation. The results indicate that enzymes can be produced from the stillage stream as a high-value coproduct in second-generation bioethanol plants in a way that also facilitates recirculation of process water.
一株表达枝顶孢霉内切葡聚糖酶Cel7B的重组黑曲霉菌株在甘蔗渣和云杉木的废水解产物（酒糟）上生长。这些废水解产物是生产Cel7B的黑曲霉D15[egI]菌株优良的生长培养基，该菌株在废水解产物中的内切葡聚糖酶活性高于在单糖含量相当的标准培养基中的活性（例如，甘蔗渣废水解产物中为2100 nkat/ml，而在基于葡萄糖的标准培养基中为480 nkat/ml）。此外，黑曲霉D15[egI]还能够消耗或转化其他木质纤维素衍生化合物，如乙酸、呋喃醛和酚类化合物，这些化合物在乙醇发酵过程中被认为是酵母的抑制剂。结果表明，在第二代生物乙醇工厂中，可以从酒糟流中生产酶作为高价值的副产品，同时还能促进工艺用水的循环利用。
