Day 2 :
University of Liège, Belgium
Keynote: LIP2 promoter as a tool for high yield recombinants protein production in the yeast Yarrowia lipolytica
Time : 09:20-10:00
Patrick Fickers has completed a PhD in Biochemistry from University of Liège (Belgium). After a Post-doc at Polytech’Lille (France), he joined in 2005, the Centre of Protein Engineering (Liège, Belgium) as an FNRS Fellow. From 2009 until 2014, he was an Associated Professor at Université libre de Bruxelles and the Head of the Biotechnology and Bioprocess Unit. Since 2015, he is a Professor at Gembloux Agro BioTech, University of Liege, in the Microbial Processes. He has published more than 49 research papers in peer-reviewed journals, six book chapters and three patents. His researches focus on the development of yeast strains by metabolic engineering and on process development in bioreactor for the production of compounds of biotechnological interest.
Non-conventional yeasts such as Y. lipolytica are considered as new cell factories for the production of recombinant proteins either at lab or industrial scale. Despite dozens of recombinant proteins have been successfully produced in this yeast, only a few expression vectors based on regulated promoters have been developed so far. Among them, promoters of key genes, namely LIP2 and POX2, of Yarrowia’s unique hydrophobic substrates metabolism have been particularly considered. Despite they are even used at industrial scale, their fine regulation is not fully understood yet. Therefore, the characterization of their regulation in regards to cell physiology, and more interestingly in function of carbon metabolism, has been the focus of this work. Our methodology was based on gene expression profiling by mean of a DsRED-reporter system or by qPCR in regard to the carbon source of the culture medium (i.e. glucose, glycerol, oleic acid, alone or in combination). For co-substrate cultures, population heterogeneity was also investigated by flow cytometry at the level carbon source uptake and intracellular lipid accumulation. Our observations have highlighted that Y. lipolytica is able to consume simultaneously glucose and oleic acid and that cell population heterogeneity is more related to a continuum of different phenotypes of cells co-consuming both carbon sources rather than having two separate sub-populations leading to producing and non-producing phenotypes. Moreover, expression of pLIP2 driven genes were more than ten-fold increase in medium containing glucose and oleic acid compared to pure hydrophobic substrate based medium.
Kio University, Japan
Keynote: Antioxidant potential in non-extractable fractions of dried persimmon (Diospyros kaki Thunb.)
Time : 10:00-10:40
Shin-ichi Kayano graduated from the Department of Food Science and Nutrition, Faculty of Human Life Science, Osaka City University, Japan, in 1985. He worked as a Senior Researcher of research institute, Miki Corporation, Japan, from 1985 through 2004. His job in Miki Corporation was the development of new products of functional foods, and study on functional components in fruits and vegetables. He was awarded a PhD in Science in 2004, from Osaka City University, Japan, under the supervision of Professor Nobuji Nakatani. He joined the Kio University as a Professor in 2009. His current study is on the antioxidative, antimutagenic, and estrogenic ingredients in various fruits and vegetables, and the elucidation of chemical structures and action mechanism of these compounds.
Dried fruits of persimmon (Diospyros kaki Thunb.) are a traditional food in Japan and contain large quantities of tannins. In this study, we investigated the in vitro and in vivo antioxidant potentials of non-extractable fractions from dried persimmons. Hydrolysed non-extractable fractions showed the highest antioxidant activities in vitro. In subsequent experiments, the plasma oxygen radical absorbance capacity (ORAC) values in rats supplemented with 5% non-extractable fraction were approximately 1.5 times higher than those in control rats after 1 week in vivo. Furthermore, using an in vitro model of the gastrointestinal tract, the ORAC values of the non-extractable fraction were significantly increased with colonic fermentation in the large bowel stage. These data indicate that non-extractable fractions may possess significant antioxidant potential in vitro and in vivo.