Abstract: A method for separating virus-like particles from a cell suspension of host cells. The virus-like particles having at least one envelope protein embedded in a lipid double membrane including at least a portion corresponding to a small envelope protein of a virus of the family Hepadnaviridae. The host cells are disrupted to obtain a first suspension. A supernatant containing the virus-like particles is separated from the first suspension. Then, an adsorbent is added to the supernatant and separated off. Then, the virus-like particles are desorbed from the adsorbent by adding a desorption buffer. A soluble calcium salt is added to a supernatant separated from the second suspension to form a precipitate, the precipitate formed is separated off and transferred to a third suspension. The virus-like particles are separated from the third suspension and purified.

Abstract: A heterologous protein is produced by a method in which yeast-type host cells are prepared, which, in addition to the at least one endogenous homologous DNA sequence coding for a first calnexin, includes at least one recombinant DNA sequence coding for the protein and at least one additional recombinant DNA sequence coding for at least one second calnexin. The protein in the host cell represents a heterologous secretable protein. The host cells are induced to express the heterologous protein via the at least one sequence coding for the protein and to overexpress calnexins by the at least one additional sequence coding for the at least one second calnexin. The host cells are then induced to secrete the heterologous protein. The secreted heterologous protein is then separated off.