Abstract
The yeast strain Yarrowia lipolytica IPS 21 was tested for its ability to produce the protease enzyme on analytically pure carbon sources as well as on waste carbon sources. It was confirmed that the yeast Y. lipolytica IPS21 can have a higher proteolytic activity in the presence of waste carbon sources in chrome-tanned leather shavings (CTLS) than on yeast extract alone. This is confirmed by the high concentration of amino acids in samples with CTLS, suggesting increased degradation of CTLS by Y. lipolytica or secretion of proteases into the medium. It was also confirmed that metals accumulate mainly in the biomass and not in the supernatant. The biomass was also found to contain high levels of Ca, K and P, which are essential for plant growth. These results show that Y. lipolytica strain IPS21 can be used for the production of extracellular alkaline proteases and for the degradation of protein waste.