在5 L发酵罐中对α-L-鼠李糖苷酶进行小试发酵，制备酶液；以聚乙烯醇-海藻酸钠为包埋载体，以戊二醛为交联剂对该酶进行固定化。经5 L罐高密度发酵96 h，α-L-鼠李糖苷酶酶活为2 766 U/g，生物量为228 g/L。经过固定化后，α-L-鼠李糖苷酶的酶活为20 U/g，酶活回收率为32.88%，固定化α-L-鼠李糖苷酶的最适反应温度为35～50 ℃，最适反应pH值为4.0，该固定化酶在连续使用6次后酶活仍然保留98.22%。高密度发酵能显著提高酶的产量，同时固定化技术提高了酶的重复利用率，为该酶利用芦丁酶法转化制备异槲皮苷提供了依据。

α-L-rhamnosidase produced by high density fermentation was immobilized into matrix consisting of polyvinyl alcohol and sodium alginate with glutaraldehyde as crosslinker. In the 5 L bioreactor, the activity of immobilized enzyme achieved 2 766 U/g and its biomass reached 228 g /L after 96 h cultivation. The enzyme activity recovery of 32.88% was obtained and the activity of immobilized enzyme was 20 U/g. The optimal temperature was 35-50 ℃ and the optimal reaction pH at about 4.0 for immobilized enzyme. The residual enzyme activity could retain more than 98.22% after 6 batches of recycling use. These results suggested that the high density fermentation could effectively enhance enzyme production, and the immobilization technology could improve enzyme recycling rate, which would offer a basis for large-scale production of isoquercitrin.