Removal of proteases from Clostridium perfringens fermented broth by aqueous two-phase systems (PEG/citrate) - Porto, Tatiana Souza; Pessôa Filho, Pedro de Alcântara; Barros Neto, Benício de; Lima Filho, José Luiz de; Converti, Attilio; Porto, Ana Lúcia Figueiredo; Pessoa Junior, Adalberto (Journal of Industrial Microbiology and Biotechnology, 2007)