酵母单细胞蛋白的制备提取(英文版).docVIP

Appl Biochem Biotechnol (2008) 148:119–129 DOI 10.1007/s12010-007-8046-6 Yeast Biomass Production in Brewery’s Spent Grains Hemicellulosic Hydrolyzate Luís C. Duarte Florbela Carvalheiro Sónia Lopes Inês Neves Francisco M. Gírio Received: 17 May 2007 / Accepted: 4 September 2007 / Published online: 26 September 2007 # Humana Press Inc. 2007 Abstract Yeast single-cell protein and yeast extract, in particular, are two products which have many feed, food, pharmaceutical, and biotechnological applications. However, many of these applications are limited by their market price. Specifically, the yeast extract requirements for culture media are one of the major technical hurdles to be overcome for the development of low-cost fermentation routes for several top value chemicals in a biorefinery framework. A potential biotechnical solution is the production of yeast biomass from the hemicellulosic fraction stream. The growth of three pentose-assimilating yeast cell factories, Debaryomyces hansenii, Kluyveromyces marxianus, and Pichia stipitis was compared using non-detoxified brewery’s spent grains hemicellulosic hydrolyzate supple- mented with mineral nutrients. The yeasts exhibited different specific growth rates, biomass productivities, and yields being D. hansenii as the yeast species that presented the best performance, assimilating all sugars and noteworthy consuming most of the hydrolyzate inhibitors. Under optimized conditions, D. hansenii displayed a maximum specific growth rate, biomass yield, and productivity of 0.34 h?1, 0.61 g g?1, and 0.56 g l?1 h?1, respectively. The nutritional profile of D. hansenii was thoroughly evaluated, and it compares favorably to others reported in literature. It contains considerable amounts of some essential amino acids and a high ratio of unsaturated over saturated fatty acids. Keywords Debaryomyces hansenii . Biomass . Single-cell protein . Hemicellulosic hydrolyzate . Brewery’s spent grains . Agro-industrial residues upgradin