Yeast flocculation: New story in fuel ethanol production.

Yeast flocculation has been used in the brewing industry to facilitate biomass recovery for a long time, and thus its mechanism of yeast flocculation has been intensively studied. However, the application of flocculating yeast in ethanol production garnered attention mainly in the 1980s and 1990s. In this article, updated research progress in the molecular mechanism of yeast flocculation and the impact of environmental conditions on yeast flocculation are reviewed. Construction of flocculating yeast strains by genetic approach and utilization of yeast flocculation for ethanol production from various feedstocks were presented. The concept of self-immobilized yeast cells through their flocculation is revisited through a case study of continuous ethanol fermentation with the flocculating yeast SPSC01, and their technical and economic advantages are highlighted by comparing with yeast cells immobilized with supporting materials and regular free yeast cells as well. Taking the flocculating yeast SPSC01 as an example, the ethanol tolerance of the flocculating yeast was also discussed.

[1]  G. T. Tsao,et al.  Preparation and performance of immobilized yeast cells in columns containing no inert carrier , 1983, Biotechnology and bioengineering.

[2]  K. Verstrepen,et al.  Late Fermentation Expression of FLO1 in Saccharomyces Cerevisiae1 , 2001 .

[3]  D. O'Shea,et al.  The influence of morphology on geldanamycin production in submerged fermentations of Streptomyces hygroscopicus var. geldanus , 2008, Applied Microbiology and Biotechnology.

[4]  M. Penttilä,et al.  Construction of a flocculent Saccharomyces cerevisiae strain secreting high levels of Aspergillus niger β-galactosidase , 2002, Applied Microbiology and Biotechnology.

[5]  T. G. Villa,et al.  Flocculation of industrial and laboratory strains ofSaccharomyces cerevisiae , 1995, Journal of Industrial Microbiology.

[6]  Fran Lewitter,et al.  Intragenic tandem repeats generate functional variability , 2005, Nature Genetics.

[7]  G. Fink,et al.  Feedback control of morphogenesis in fungi by aromatic alcohols. , 2006, Genes & development.

[8]  Xinqing Zhao,et al.  Improving ethanol tolerance of a self-flocculating yeast by optimization of medium composition , 2008 .

[9]  G. Braus,et al.  Differential Flo8p-dependent regulation of FLO1 and FLO11 for cell–cell and cell–substrate adherence of S. cerevisiae S288c , 2007, Molecular microbiology.

[10]  Xin-Qing Zhao,et al.  Continuous ethanol production using self-flocculating yeast in a cascade of fermentors , 2005 .

[11]  Wei Shen,et al.  Construction of a flocculating yeast for fuel ethanol production , 2007, Biotechnology Letters.

[12]  E. V. Soares,et al.  Flocculation onset in Saccharomyces cerevisiae: effect of ethanol, heat and osmotic stress , 2007, Journal of applied microbiology.

[13]  T. Koloini,et al.  Impact of pellet size on growth and lignin peroxidase activity of Phanerochaete chrysosporium , 2006 .

[14]  A. Teunissen,et al.  The dominant flocculation genes of Saccharomyces cerevisiae constitute a new subtelomeric gene family , 1995, Yeast.

[15]  Yoshihito Shirai,et al.  Flocculation characteristics of an isolated mutant flocculent Saccharomyces cerevisiae strain and its application for fuel ethanol production from kitchen refuse. , 2009, Bioresource technology.

[16]  X. Ge,et al.  Impact of zinc supplementation on the improvement of ethanol tolerance and yield of self-flocculating yeast in continuous ethanol fermentation. , 2009, Journal of biotechnology.

[17]  Sílvia K Missawa,et al.  Control by sugar of Saccharomyces cerevisiae flocculation for industrial ethanol production. , 2006, FEMS yeast research.

[18]  R. Kuroki,et al.  Region of Flo1 Proteins Responsible for Sugar Recognition , 1998, Journal of bacteriology.

[19]  M. R. Sharifmoghadam,et al.  The fission yeast Map4 protein is a novel adhesin required for mating , 2006, FEBS letters.

[20]  Nan Liu,et al.  Genetic basis of flocculation phenotype conversion in Saccharomyces cerevisiae. , 2007, FEMS yeast research.

[21]  I. Sá-Correia,et al.  Influence of Calcium Ion on Ethanol Tolerance of Saccharomyces bayanus and Alcoholic Fermentation by Yeasts , 1988, Applied and environmental microbiology.

[22]  R. Korus,et al.  Ethanol fermentation in a continuous tower fermentor , 1984, Biotechnology and bioengineering.

[23]  C. Ghommidh,et al.  Influence of Yeast Flocculation on the Rate of Jerusalem Artichoke Extract Fermentation , 2000, Current Microbiology.

[24]  K. Kida,et al.  Repeated-Batch Ethanol Fermentation by a Flocculating Yeast, Saccharomyces cerevisiae IR-2 , 1991 .

[25]  X. Ge,et al.  Intrinsic kinetics of continuous growth and ethanol production of a flocculating fusant yeast strain SPSC01. , 2006, Journal of biotechnology.

[26]  Xumeng Ge,et al.  Impacts of temperature, pH, divalent cations, sugars and ethanol on the flocculating of SPSC01 , 2006 .

[27]  P. Lipke,et al.  A Biochemical Guide to Yeast Adhesins: Glycoproteins for Social and Antisocial Occasions , 2007, Microbiology and Molecular Biology Reviews.

[28]  W. Lo,et al.  FLO11, a yeast gene related to the STA genes, encodes a novel cell surface flocculin , 1996, Journal of bacteriology.

[29]  R. Raghav,et al.  Ethanolic fermentation of cane molasses by a highly flocculent yeast , 1989, Biotechnology Letters.

[30]  K. Kida,et al.  The effect of aeration on stability of continuous ethanol fermentation by a flocculating yeast. , 1989 .

[31]  Continuous tower fermentation for power ethanol production , 1982, Biotechnology Letters.

[32]  K. Foster,et al.  FLO1 Is a Variable Green Beard Gene that Drives Biofilm-like Cooperation in Budding Yeast , 2008, Cell.

[33]  K. Kida,et al.  Continuous high-ethanol fermentation from cane molasses by a flocculating yeast☆ , 1990 .

[34]  Cora Styles,et al.  Genetic and Epigenetic Regulation of the FLO Gene Family Generates Cell-Surface Variation in Yeast , 2004, Cell.

[35]  K. Kida,et al.  Ethanol production by repeated-batch fermentation at high temperature in a molasses medium containing a high concentration of total sugar by a thermotolerant flocculating yeast with improved salt-tolerance , 1997 .

[36]  A. Brandt,et al.  Flocculation in Saccharomyces cerevisiae is repressed by the COMPASS methylation complex during high‐gravity fermentation , 2008, Yeast.

[37]  I. S. Pretorius,et al.  Characteristics of Flo11-dependent flocculation in Saccharomyces cerevisiae. , 2005, FEMS yeast research.

[38]  B. Gibson,et al.  Yeast responses to stresses associated with industrial brewery handling. , 2007, FEMS microbiology reviews.

[39]  L. Domingues,et al.  Fermentation of high concentrations of lactose to ethanol by engineered flocculent Saccharomyces cerevisiae , 2008, Biotechnology Letters.

[40]  S. Müller,et al.  Prediction of flocculation ability of brewing yeast inoculates by flow cytometry, proteome analysis, and mRNA profiling , 2009, Cytometry. Part A : the journal of the International Society for Analytical Cytology.

[41]  L. Ingram,et al.  Effects of alcohols on micro-organisms. , 1984, Advances in microbial physiology.

[42]  S. Shioya,et al.  Effect of flocculation on performance of arming yeast in direct ethanol fermentation , 2006, Applied Microbiology and Biotechnology.

[43]  J. Barford,et al.  Tower fermentation of sugar cane juice , 1982, Biotechnology Letters.

[44]  J. Jiménez,et al.  Adaptive evolution by mutations in the FLO11 gene. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[45]  H. Hoshida,et al.  Construction of Flocculent Kluyveromyces marxianus Strains Suitable for High-Temperature Ethanol Fermentation , 2009, Bioscience, biotechnology, and biochemistry.

[46]  J. Sierra,et al.  Effect of temperature in the evaluation of yeast flocculation ability by the Helm's method , 1996 .

[47]  H. Verachtert,et al.  Yeast flocculation: what brewers should know , 2003, Applied Microbiology and Biotechnology.

[48]  I. S. Pretorius,et al.  Controlled Expression of the Dominant Flocculation Genes FLO1, FLO5, and FLO11 in Saccharomyces cerevisiae , 2008, Applied and Environmental Microbiology.

[49]  J. Teixeira,et al.  Effect of cultural and nutritional conditions on the control of flocculation expression in Saccharomyces cerevisiae. , 1994, Canadian journal of microbiology.

[50]  G. Fink,et al.  Saccharomyces cerevisiae S288C has a mutation in FLO8, a gene required for filamentous growth. , 1996, Genetics.

[51]  G. Smit,et al.  Determinants of flocculence of brewer's yeast during fermentation in wort , 1993, Yeast.

[52]  W. Lo,et al.  The cell surface flocculin Flo11 is required for pseudohyphae formation and invasion by Saccharomyces cerevisiae. , 1998, Molecular biology of the cell.

[53]  X. Ge,et al.  Online monitoring and characterization of flocculating yeast cell flocs during continuous ethanol fermentation. , 2005, Biotechnology and bioengineering.

[54]  Chunkeng Hu,et al.  [Effect of flocculence of a self-flocculating yeast on its tolerance to ethanol and the mechanism]. , 2005, Sheng wu gong cheng xue bao = Chinese journal of biotechnology.

[55]  L. Domingues,et al.  Alcohol production from cheese whey permeate using genetically modified flocculent yeast cells. , 2001, Biotechnology and bioengineering.

[56]  A. Dranginis,et al.  Expression and Characterization of the Flocculin Flo11/Muc1, a Saccharomyces cerevisiae Mannoprotein with Homotypic Properties of Adhesion , 2007, Eukaryotic Cell.

[57]  Mohammad J. Taherzadeh,et al.  A Possible Industrial Solution to Ferment Lignocellulosic Hydrolyzate to Ethanol: Continuous Cultivation with Flocculating Yeast , 2007, International Journal of Molecular Sciences.

[58]  C. Gustafsson,et al.  Molecular phylogenetics of ascomycotal adhesins--a novel family of putative cell-surface adhesive proteins in fission yeasts. , 2008, Fungal genetics and biology : FG & B.

[59]  K. Verstrepen,et al.  Flocculation, adhesion and biofilm formation in yeasts , 2006, Molecular microbiology.

[60]  K. Verstrepen,et al.  Phenotypic diversity of Flo protein family-mediated adhesion in Saccharomyces cerevisiae. , 2009, FEMS yeast research.

[61]  M. Stratford,et al.  Yeast flocculation: a new perspective. , 1992, Advances in microbial physiology.

[62]  M. Stratford,et al.  Evidence for two mechanisms of flocculation in Saccharomyces cerevisiae. , 1989, Yeast.

[63]  X. Ge,et al.  An innovative consecutive batch fermentation process for very high gravity ethanol fermentation with self-flocculating yeast , 2009, Applied Microbiology and Biotechnology.

[64]  S. Assinder,et al.  Yeast flocculation: Flo1 and NewFlo phenotypes and receptor structure , 1991, Yeast.

[65]  F. Bai,et al.  Mechanisms of yeast stress tolerance and its manipulation for efficient fuel ethanol production. , 2009, Journal of biotechnology.

[66]  L. Ingram,et al.  Magnesium limitation and its role in apparent toxicity of ethanol during yeast fermentation , 1986, Applied and environmental microbiology.

[67]  G. Fink,et al.  Origins of variation in the fungal cell surface , 2004, Nature Reviews Microbiology.

[68]  G. Goma,et al.  Ethanol fermentation by flocculating yeast: Performance and stability dependence on a critical fermentation rate , 1985, Biotechnology Letters.

[69]  M. Takagi,et al.  Breeding of flocculent industrial alcohol yeast strains by self-cloning of the flocculation gene FLO1 and repeated-batch fermentation by transformants. , 1998, The Journal of general and applied microbiology.

[70]  G. Fink,et al.  A Saccharomyces gene family involved in invasive growth, cell-cell adhesion, and mating. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[71]  A. Brandt,et al.  Fermentation of High Concentrations of Maltose by Saccharomyces cerevisiae Is Limited by the COMPASS Methylation Complex , 2006, Applied and Environmental Microbiology.

[72]  M. D. Ferrari,et al.  Ethanol production from eucalyptus wood hemicellulose hydrolysate by Pichia stipitis , 1992, Biotechnology and bioengineering.

[73]  H. Tettelin,et al.  In silicio identification of glycosyl‐phosphatidylinositol‐anchored plasma‐membrane and cell wall proteins of Saccharomyces cerevisiae , 1997, Yeast.

[74]  M. Ueda,et al.  High-level ethanol production from starch by a flocculent Saccharomyces cerevisiae strain displaying cell-surface glucoamylase , 2002, Applied Microbiology and Biotechnology.

[75]  Gerald R. Fink,et al.  Unipolar cell divisions in the yeast S. cerevisiae lead to filamentous growth: Regulation by starvation and RAS , 1992, Cell.

[76]  A. Bakalinsky,et al.  FLO11-Based Model for Air-Liquid Interfacial Biofilm Formation by Saccharomyces cerevisiae , 2005, Applied and Environmental Microbiology.

[77]  X. Ge,et al.  Ethanol tolerance and the variation of plasma membrane composition of yeast floc populations with different size distribution. , 2007, Journal of biotechnology.

[78]  R. Speers,et al.  Effect of Environmental Conditions on the Flocculation of Saccharomyces Cerevisiae , 2000 .