Extraction of tetracycline from fermentation broth using aqueous two-phase systems composed of polyethylene glycol and cholinium-based salts - Pereira, Jorge F. B; Vicente, Filipa; Santos-Ebinuma, Valéria de Carvalho; Araujo, Janete Magali de; Pessoa Junior, Adalberto; Freire, Mara G; Coutinho, João A. P (Process Biochemistry, 2013)