Protoplast isolation from cultured lichen Usnea ghattensis, their fusion with protoplasts of Aspergillus nidulans, fusant regeneration and production of usnic acid.

Protoplasts isolated from the mycobiont of a cultured lichen Usnea ghattensis were fused with protoplasts of the fungus Aspergillus nidulans in order to increase the growth rate of the cultured lichen mycobiont in vitro. The maximum protoplast yield (102 x 10(4)/g fresh cell mass) was reached in citrate buffer with 50 mmol/L 2-sulfanylethanol ('2-mercaptoethanol') containing 0.1 % Novozym after 1.5 h at pH 5 and