A lysine sensor for process control of lysine fermentation was developed based on a Clark‐type electrode in combination with L‐lysine‐α‐oxidase. The enzyme, isolated from Trichoderma viride, was immobilized between a cellulose and a polypropylene foil using a polyurethane resin. Lysine determinations were carried out in a flow‐through system as anodic measurements when H2O2 was measured and as chathodic measurements when the consumption of O2 was followed. The sensitivity of the sensor toward other amino acids was determined.

A L‐lysine α‐oxidase (LOD) has been purified to homogeneity in a two‐step procedure with 300‐fold enrichment and 60% recovery from the culture extract of Trichoderma viride i4. The enzyme catalyzes the reaction between L‐lysine and molecular oxygen forming 2‐oxo‐6‐aminocaproate, ammonia and hydrogen peroxide. Numerous substrates have been tested. The Km value for L‐lysine was found to be 0.026 mM. Its apparent molecular mass is 110000 Da when determined by gel filtration on Sephadex G‐200, the estimated molecular weight of the subunits being 55000 Da in the SDS‐PAGE. The enzyme is a glycoprotein and shows absorption maxima at 276, 386 and 463 nm. It was found to contain 1 mol of FAD per subunit. The coenzyme is bound non‐covalently. Its isoelectric point is at pH 4.3. The enzyme is stable at extreme pH values, at relatively high temperatures and in diluted hydrogen peroxide.The enzyme described here differs from two other known L‐lysine oxidases previously characterized with regard to its amino acid composition and its substrate specificity.

In Langzeit-lnkubationsversuchen wurden die Auswirkungen abgestufter Mengen von chemisch ver~inderter (N-modifizierter) Braunkohle auf die mikrobiologischen und enzymatischen Umsatzleistungen in verschiedenen Kippsubstraten geprfift. Die Untersuchungsbefunde charakterisieren diesen Humusdiingestoff als ein dauerhafl wirksames organisches Bodenverbesserungsmittel mit N-Diingewirkung, das die bodenmikrobiologischen Aktivit~-ten verbessert.Stichw6rter: N-modifizierte Braunkohle; mikrobiologischer Umsatz; Humusdtingestoff; toxische Stoffe EFFECT OF N-MODIFED BROWN COAL ON THE SOIL BIOLOGYIn long term-incubation tests effects of blended amounts of chemical changed (N-modified) brown coal on the microbiological turnovers are investigated in various dump substrates. The results characterise this humus fertilizer as poor in noxious substances and as a long lasting acting organic soil improving agent including a N-fertilising effect.