TY - JOUR

T1 - Assessing Ionizing Radiation and Chlorine Dioxide (ClO2) as Potential Aseptization Treatments for Yeast Recycling on Mixed Wort of Corn and Sugarcane in Brazil

AU - Douradinho, Rafael

AU - Sica, Pietro

AU - Oliveira, Matheus

AU - Uchoa Pinto, Alana

AU - Mota, Layna

AU - Mattos, Eduardo

AU - Perecin, Danilo

AU - Garcilasso, Vanessa

AU - de Almeida, João Monnerat Araujo Ribeiro

AU - Piedade, Sonia

AU - Alves, Lucílio

AU - Arthur, Valter

AU - Coelho, Suani

AU - Baptista, Antonio

N1 - Publisher Copyright: © 2024 by the authors.

PY - 2024

Y1 - 2024

N2 - Yeast recycling, which is a common practice in sugarcane ethanol plants, could be expanded if it could be successfully implemented in corn-based ethanol production. However, the process of recycling the yeast remaining after fermentation is hampered by contaminating microorganisms that reduce the fermentation efficiency and compete with the yeast for the fermentable sugars. Currently, antibiotics are used to control microbial contamination. This study proposes chlorine dioxide and electron beam irradiation as alternative control methods for completely inactivating contaminants and minimizing their effect on recycled yeast. For that, wort sterilization using electron radiation (20 kGy) and treatment with a chemical biocide, namely chlorine dioxide (125 mg kg−1), were compared with non-treated wort. Five fermentation cycles were performed using fed-batch systems with 300 g L−1 of fermentable sugars. The results obtained in this study showed the inactivation of contaminants under the effect of electron beam irradiation, which led to an increase in the productivity, yield, and efficiency of fermentation by 0.21 g L−1h−1, 2.6%, and 4.7%, respectively. However, ClO2 did not show promising results in reducing contamination or improving fermentative parameters. Thus, electron beam irradiation of contaminated wort may be a suitable alternative to chemical biocides and would allow the use of recycled yeast in corn-based ethanol plants.

AB - Yeast recycling, which is a common practice in sugarcane ethanol plants, could be expanded if it could be successfully implemented in corn-based ethanol production. However, the process of recycling the yeast remaining after fermentation is hampered by contaminating microorganisms that reduce the fermentation efficiency and compete with the yeast for the fermentable sugars. Currently, antibiotics are used to control microbial contamination. This study proposes chlorine dioxide and electron beam irradiation as alternative control methods for completely inactivating contaminants and minimizing their effect on recycled yeast. For that, wort sterilization using electron radiation (20 kGy) and treatment with a chemical biocide, namely chlorine dioxide (125 mg kg−1), were compared with non-treated wort. Five fermentation cycles were performed using fed-batch systems with 300 g L−1 of fermentable sugars. The results obtained in this study showed the inactivation of contaminants under the effect of electron beam irradiation, which led to an increase in the productivity, yield, and efficiency of fermentation by 0.21 g L−1h−1, 2.6%, and 4.7%, respectively. However, ClO2 did not show promising results in reducing contamination or improving fermentative parameters. Thus, electron beam irradiation of contaminated wort may be a suitable alternative to chemical biocides and would allow the use of recycled yeast in corn-based ethanol plants.

KW - bioenergy

KW - biofuel

KW - corn ethanol

KW - disinfection

KW - electron beam

KW - fermentation

KW - ionizing radiation

KW - microbial contamination

KW - sterilization

KW - yeast recycling

U2 - 10.3390/stresses4010009

DO - 10.3390/stresses4010009

M3 - Journal article

AN - SCOPUS:85188924332

VL - 4

SP - 155

EP - 171

JO - Stresses

JF - Stresses

SN - 2673-7140

IS - 1

ER -