α-Glucosidase is a crucial enzyme for the production of isomaltooligosaccharide. In this study, a novel method comprising eosin Y (EY) and α-d-methylglucoside (AMG) in glass plates was tested for the primary screening of α-glucosidaseproducing strains. First, α-glucosidase-producing Aspergillus niger strains were selected on plates containing EY and AMG based on transparent zone formation resulting from the solubilization of EY by the hydrolyzed product. Conventional methods that use trypan blue (TB) and p-nitrophenyl-α-d-glucopyranoside (pPNP) as indicators were then compared with the new strategy. The results showed that EY-containing plates provide the advantages of low price and higher specificity for the screening of α-glucosidase-producing strains. We then evaluated the correlation between the hydrolytic activity of α-glucosidase and diffusion distance, and found that good linearity could be established within a 6–75 U/ml enzyme concentration range. Finally, the hydrolytic and transglycosylation activities of α-glucosidase obtained from the target isolates were determined by EY plate assay and 3,5-dinitrosalicylic acid-Saccharomyces cerevisiae assay, respectively. The results showed that the diameter of the transparent zone varied among isolates was positively correlated with α-glucosidase hydrolytic activity, while good linearity could also be established between α-glucosidase transglycosylation activity and non-fermentable reducing sugars content. With this strategy, 7 Aspergillus niger mutants with high yield of α-glucosidase from 200 obvious single colonies on the primary screen plate were obtained.

中文翻译：

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筛选生产α-葡萄糖苷酶的微生物的策略的发展

α-葡萄糖苷酶是产生异麦芽低聚糖的关键酶。在这项研究中，测试了一种在玻璃板中包含曙红Y（EY）和α- d-甲基葡萄糖苷（AMG）的新方法，用于初步筛选产生α-葡萄糖苷酶的菌株。首先，基于由水解产物使EY溶解而产生的透明区，在包含EY和AMG的平板上选择产生α-葡糖苷酶的黑曲霉菌株。使用台盼蓝（TB）和对硝基苯基-α- d的常规方法然后，以吡喃葡萄糖苷（pPNP）为指标与新策略进行了比较。结果表明，含EY的平板具有价格低廉和对生产α-葡萄糖苷酶菌株的特异性更高的优势。然后，我们评估了α-葡萄糖苷酶的水解活性与扩散距离之间的相关性，发现可以在6–75 U / ml的酶浓度范围内建立良好的线性。最后，通过EY平板分析和3,5-二硝基水杨酸-酿酒酵母测定了从目标分离物中获得的α-葡萄糖苷酶的水解和转糖基化活性。化验。结果表明，分离株之间透明区直径的变化与α-葡萄糖苷酶的水解活性呈正相关，而α-葡萄糖苷酶的转糖基化活性与不可发酵还原糖含量之间也可建立良好的线性关系。通过该策略，从初级筛选板上的200个明显的单个菌落中获得了具有高产率的α-葡萄糖苷酶的7个黑曲霉突变体。