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Production of D-amino-acid oxidase by Trigonopsis variabilis has been investigated using a two-stage cultivation technique. After transfer of exponentially growing cells to fresh medium, the enzyme was induced by addition of D-amino acids to the growth medium, among which D-methionine and D-alanine were the most effective. The simultaneous presence of the L form of amino acids or [Formula: see text] did not affect this induction. The presence of trace metals, inorganic phosphate, and a high rate of agitation were necessary for formation of maximal D-amino-acid oxidase activity. The enzyme is not subject to glucose repression.

Monoclonal antibodies have been used to determine the presence of cellobiohydrolases I and II (CBH I and II), and endoglucanase I (EG I) on the surface of conidia from Trichoderma reesei QM 9414 and RUT C-30, and 8 other Trichoderma species. For this purpose, proteins were released from the conidial surface by treatment with a non-ionic detergent (Triton X-100 and beta-octylglucoside), followed by SDS-PAGE/Western blotting and immunostaining. Both CBH I and II were clearly present, but - unlike in extracellular culture fluids from Trichoderma - CBH II was the predominant cellulase. In T. reesei EG I could not be detected. The higher producer strain T. reesei RUT C-30 exhibited a higher conidial level of CBH II than T. reesei QM 9414. In order to assess the importance of the conidial CBH II level for cellulase induction by cellulose, multiple copies of the chb2 gene were introduced into the T. reesei genome by cotransformation using PyrG as a marker. Stable multicopy transformants secreted the 2- to 4-fold level of CBH II into the culture medium when grown on lactose as a carbon source, but their CBH I secretion was unaltered. Upon growth on cellulose, both CBH I and CBH II secretion was enhanced. Those strain showing highest cellulase activity on cellulose also appeared to contain the highest level of conidial bound CBH II. CBH II was also the predominant conidial cellulase in various other Trichoderma sp. However, roughly the same amount of conidial bound CBH II was detected in all strains, although their cellulase production differed considerably.

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