title: Polyhexamethyl biguanide can eliminate contaminant yeasts from fuel-ethanol fermentation process.
abstract: Industrial ethanol fermentation is a non-sterile process and contaminant microorganisms can lead to a decrease in industrial productivity and significant economic loss. Nowadays, some distilleries in Northeastern Brazil deal with bacterial contamination by decreasing must pH and adding bactericides. Alternatively, contamination can be challenged by adding a pure batch of Saccharomyces cerevisiae-a time-consuming and costly process. A better strategy might involve the development of a fungicide that kills contaminant yeasts while preserving S. cerevisiae cells. Here, we show that polyhexamethyl biguanide (PHMB) inhibits and kills the most important contaminant yeasts detected in the distilleries of Northeastern Brazil without affecting the cell viability and fermentation capacity of S. cerevisiae. Moreover, some physiological data suggest that PHMB acts through interaction with the yeast membrane. These results support the development of a new strategy for controlling contaminant yeast population whilst keeping industrial yields high.
authors.affiliation: Departamento de Genética, Universidade Federal de Pernambuco, Av. Moraes Rego, 1235 Cidade Universitária, 50670-901, Recife, Pernambuco, Brazil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Elsztein
authors.forename: João Assis Scavuzzi
authors.initials: JA
authors.lastname: de Menezes
authors.forename: Marcos Antonio
authors.initials: MA
authors.lastname: de Morais
mesh_terms: D001645:Biguanides / Q000737:chemistry / Q000494:pharmacology*; D003470:Culture Media; D025141:Drug Resistance, Fungal / Q000187:drug effects; D000431:Ethanol / Q000378:metabolism* / Q000494:pharmacology; D005285:Fermentation; D005659:Fungicides, Industrial / Q000494:pharmacology*; D005947:Glucose / Q000494:pharmacology; D007218:Industrial Microbiology; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D016019:Survival Analysis; D015003:Yeasts / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D001645:Biguanides; D003470:Culture Media; D005659:Fungicides, Industrial; C031233:polihexanide; D000431:Ethanol; D005947:Glucose