HETEROLOGOUS PROTEIN SECRETION BY ASPERGILLUS-NIGER GROWING IN SUBMERGED CULTURE AS DISPERSED OR AGGREGATED MYCELIA

The secreted production of a heterologous enzyme, hen egg-white lysozy me, by Aspergillus niger was studied in shake flasks containing media of different initial viscosities. Raising the viscosity of the medium by addition of polyvinylpyrrolidone (PVP) brought about a transition i n the form of growth from aggregated mycelia (pellets) to dispersed my celia. The specific yield of lysozyme in cultures containing an initia l concentration of 5% (w/v) starch was 8 mg lysozyme/g dry weight. Add ition of 2% (w/v) PVP to the medium resulted in a specific yield of 14 mg lysozyme/g dry weight.