Accepted Article The role of peroxisomes in xylose alcoholic fermentation in the engineered Saccharomyces cerevisiae Running title: Peroxisomes in xylose fermentation Ljubov Dzanaeva 1 , Barbara Kruk 2 , Justyna Ruchala 2 , Jens Nielsen 3 , Andriy Sibirny 1,2 , Kostyantyn Dmytruk 1* 1 Department of Molecular Genetics and Biotechnology, Institute of Cell Biology, NAS of Ukraine, Drahomanova Street, 14/16, Lviv 79005 Ukraine; 2 Department of Biotechnology and Microbiology, University of Rzeszow, Cwiklinskiej 2, Rzeszow 35-601 Poland; 3 Department of Biology and Biological Engineering, Chalmers University of Technology, SE412 96 Gothenburg, Sweden. *Correspondence: Dr. Kostantyn Dmytruk, Department of Molecular Biology and Biotechnology, Institute of Cell Biology, NAS of Ukraine, Drahomanova Street 14/16, 79005, Lviv, Ukraine, E-mail: dmytruk77@gmail.com Abbreviation list: ROS: reactive oxygen species; GFP: green fluorescent protein. Abstract Xylose is a second most abounded sugar after glucose in lignocellulosic hydrolysates and should be efficiently fermented for economically viable second-generation ethanol production. Despite significant progress in metabolic and evolutionary engineering, xylose fermentation rate of recombinant Saccharomyces cerevisiae remains lower than that for glucose. Our recent study demonstrated that peroxisome- deficient cells of yeast Ogataea polymorpha showed decrease in ethanol production from xylose. In this work, we have studied role of peroxisomes in xylose alcoholic fermentation in the engineered xylose-utilizing strain of S. cerevisiae. It was shown that peroxisome-less pex3Δ mutant possessed 1.5-fold decrease of ethanol production from xylose. We hypothesized that peroxisomal catalase Cta1 may have importance for hydrogen peroxide, the important component of ROS, detoxification during xylose alcoholic fermentation. It was clearly shown that CTA1 deletion impaired ethanol This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/cbin.11353. This article is protected by copyright. All rights reserved.