尖镰孢胞外青霉素V酰化酶的产生

PRODUCTION OF EXTRACELLULAR PENICILLIN V ACYLASE BY FUSARIUM OXYSPORUM

由腐殖土中分离出一株产胞外青霉素Ｖ酰化酶的尖镰孢（Ｆｕｓａｒｉｕｍｏｘｙｓｐｏｒｕｍ），编号ＦＰ９４１。研究了该菌在液体培养基中产胞外青霉素Ｖ酰化酶的条件。在以１０％麦麸为碳源的培养基中，添加氮源能促进酶的形成。无机氮源优于有机氮源。（ＮＨ４）２ＨＰＯ４的促进效果最佳，草酸铵次之，用量均为１％。为提高产酶量，培养基中添加诱导物是必要的、苯氧乙酸的诱导效果最佳，用量为０．１％，其次是青霉素Ｖ，用量为０．３％。最适培养条件为：培养基起始ｐＨ７．７，２８℃振荡培养５ｄ。以青霉素Ｖ为作用底物，于ＰＨ７．０，５０℃测定，培养滤液酶活力为３．０ｕ／ｍｌ。培养滤液中未检出β－内酰胺酶。

The extracellular penicillin V acylase-producing strain named Fusarium oxysporum FP941 was obtained from a soll sample.The optimum conditions of enzyme production were investigatedwith the strain.Adding nitrogen sources can increase enzyme production for the medium with 10%wheat bran as carbon source.Inorganic nitrogen sources were more effective than.organic ones and 1% (NH4)2HPO4 was optimal.The second effective was ammonium oxalate. Adding inducers was necessary for enzyme production.Phenoxyacetic acid(0.1%) was the best.Penicillin V (0.3%) was also a goodinducer. After cultivating the strain in liquid medium containing wheat bran 10%,(NH4)2HPO4 1%,phenoxyacetic acid 0.1%(initial pH was 7.7) at 28% for 5 days,the potency of the crude filtrate acting on penicillin V was 3.0u/ ml.β lactase was not detected in culture filtrate.