Production of Polyunsaturated Fatty Acids Using Novel Cell Treatment Method

A method for storing dried cells comprising a microbial biomass containing a microorganism which has produced one compound or more than one compounds, wherein

• (1) dried cells are obtained by the following steps:
• (a) preparing or obtaining wet cells having an average moisture content of between 30% and 80%;
• (b) subjecting the wet cells to primary drying to obtain primary dried cells having an average moisture content of between 5% and 50%;
• (c) subjecting the primary dried cells obtained in (b) to secondary drying to obtain secondary dried cells having an average moisture content of no greater than 10%;
• and then
• (2) the obtained secondary dried cells are subjected to cooling treatment by one of the following methods:
• (i) cooling to at least 60° C. by supplying air having a composition with an oxygen concentration of no greater than 21%;
• or
• (ii) cooling to at least 60° C. by static cooling in an atmosphere of air having a composition with an oxygen concentration of no greater than 21%;
• and
• (3) the cooled secondary dried cells are stored by one of the following methods:
• (I) filling said cells into a sealable container together with nitrogen gas and storing them at 15° C. or below;
• or
• (II) filling said cells into a sealable container together with air having an oxygen concentration of no greater than 20%, and storing them at 15° C. or below.

A method for isolating one compound or more than one compounds from a microbial biomass containing a microorganism which has produced the compound or compounds, wherein

• (1) dried cells are obtained by the following steps:
• (a) preparing or obtaining wet cells having an average moisture content of between 30% and 80%;
• (b) disrupting the wet cells to obtain disrupted cells having an average moisture content of between 30% and 80%;
• (c) drying the disrupted cells to obtain dried cells having an average moisture content of no greater than 10%;
• and then
• (2) the obtained dried cells are subjected to cooling treatment by one of the following methods:
• (i) cooling to at least 60° C. by supplying air having a composition with an oxygen concentration of no greater than 21%;
• or
• (ii) cooling to at least 60° C. by static cooling in an atmosphere of air having a composition with an oxygen concentration of no greater than 21%;
• and
• (3) the compound or each of the compounds is purified, extracted, isolated and/or refined from the cooled dried cells.