Production of Bioingredients fromKluyveromyces marxianusGrown on Whey: An Alternative

Abstract

Whey waste is a major problem for the dairy industry. Finding alternative means to reduce its pollution potential and produce high value-added bioingredients has been attempted by many researchers. Kluyveromyces marxianus var. marxianus is a dairy yeast that produces beta-galactosidase, allowing for whey fermentation. Also, K. marxianus has been proposed as a source of: (1) oligonucleotides, used as flavor enhancers in food products; (2) oligosaccharides, used as prebiotics to stimulate the growth of Bifidobacterium sp. in the animal and human intestines; and (3) oligopeptides, immunostimulators added to dairy products that are released in the wort after whey protein proteolysis. Fed-batch fermentation can be used as an alternative process to avoid increases in lactose concentration and prevent the catabolite repression of the respiratory enzyme synthesis during aerobic fermentation, thus allowing for high biomass yields. The relevance of these factors on yeast fermentation of whey is summarized in this critical review.

Hyper-production of a thermotolerant b-xylosidase by a deoxy-D-glucose and cycloheximide resistant mutant derivative of Kluyveromyces marxianus PPY 125

“…Thermodynamic studies provided sufficient insight into the thermostability of the enzyme and may be due to accompanying chaperone activity. Endo-β-xylanase and β-xylosidase act in synergism to breakdown xylanlignin complex in paper and pulp industry (Tsujibo et al 2001) K. marxianus produces β-xylosidase with out any accompanying cellulases (Belem and Lee, 1998) This organism produces β-galactosidase, β-glucosidase, and pectinase as well (Belem and Lee, 1998) and may be suitable for biobleaching of pulps if xylanase gene could be incorporated in K. marxianus as reported by other authors (La Grange et al 2001).…”

“…Recently production of β-xylosidase has been described in K. marxianus and other yeasts (Manzanares et al 1999) but no detailed study is available on its production by wild or mutant cultures of K. marxianus. Xylose, xylobiose, synthetic β-xylosides and xylo-oligosaccharides are inducers of this enzyme in yeasts (Belem and Lee, 1998), but, like other enzymes, other carbon sources may serve as its inducers . The production of enzymes is influenced by induction and catabolite repression (de Groot et al 2003).…”

“…Kluyveromyces marxianus has been employed for production ofbiomass, enzymes and ethanol (Belem and Lee, 1998;Furlan et al 2000). Recently production of β-xylosidase has been described in K. marxianus and other yeasts (Manzanares et al 1999) but no detailed study is available on its production by wild or mutant cultures of K. marxianus.…”

Convective Drying of the Thermotolerant Kluyveromyces marxianus at Relatively Low Temperatures and its Efficiency in Whey Fermentation

“…marxianus is a yeast that produces -galactosidase, enabling whey fermentation. This yeast offers great advantages, such as good growth yield, acceptability as a safe microorganism, higher -galactosidase activity than other yeasts when lactose is used as substrate [6]. The importance of K. marxianus application in whey treatment in order to produce value added products, such as potable and gradefuel alcohol, baker's yeast and SCP, raises the need for preservation and storage of large quantities of K. marxianus biomass.…”

The NADP+-dependent glutamate dehydrogenase of the yeast Kluyveromyces marxianus responds to nitrogen repression similarly to Saccharomyces cerevisiae

“…It has been related the biotechnological use of Kluyveromyces in the "Yeast as Cell Factory" concept to produce amino acidrich biomass due to its advantageous physiological characteristics compared to S. cerevisiae: the absence of ethanol production (Crabtree-negative effect), the lower catabolic repression response, the higher flux through the glycolytic pathway (8,15) and the high capacity of the respiratory enzymes (6,15 to produce bioingredients, such as oligopeptides, oligosacharides and oligonucleotides mainly for pharmaceutical and food industries (1). Similarly to K. lactis, K. marxianus is Crabtreenegative yeast, generally regarded as safe for human and animal consumption and possesses an arsenal of hydrolytic extracellular hydrolases that enables its use for bioconversion of complex sugar-rich substrates into single cell protein.…”