Production, Distribution, and Kinetic Properties of Inulinase in Continuous Cultures of Kluyveromyces marxianus CBS 6556

Abstract

From a screening of several Kluyveromyces strains, the yeast Kluyveromyces marxianus CBS 6556 was selected for a study of the parameters relevant to the commercial production of inulinase (EC 3.2.1.7). This yeast exhibited superior properties with respect to growth at elevated temperatures (40 to 45°C), substrate specificity, and inulinase production. In sucrose-limited chemostat cultures growing on mineral medium, the amount of enzyme decreased from 52 U mg of cell dry weight-' at D = 0.1 h-l to 2 U mg of cell dry weight1 l at D = 0.8 h-'. Experiments with nitrogen-limited cultures further confirmed that synthesis of the enzyme is negatively controlled by the residual sugar concentration in the culture. High enzyme activities were observed during growth on nonsugar substrates, indicating that synthesis of the enzyme is a result of a derepression/ repression mechanism. A substantial part of the inulinase produced by K. marxianus was associated with the cell wall. The enzyme could be released from the cell wall via a simple chemical treatment of cells. Results are presented on the effect of cultivation conditions on the distribution of the enzyme. Inulinase was active with sucrose, raffinose, stachyose, and inulin as substrates and exhibited an S/I ratio (relative activities with sucrose and inulin) of 15 under standard assay conditions. The enzyme activity decreased with increasing chain length of the substrate.

Substrate‐accelerated death of Saccharomyces cerevisiae CBS 8066 under maltose stress

“…Under glucose-limited growth (derepressing conditions), considerable amounts of the enzyme were detected (Table 2). This derepressing effect during continuous cultivation at low growth rates has also been reported for the extracellular enzyme inulinase (Rouwenhorst et al, 1988).…”

Physiology of the yeastKluyveromyces marxianusduring batch and chemostat cultures with glucose as the sole carbon source

“…In spite of this, these studies have shown that K. marxianus is very versatile and could be economically explored for a very wide range of applications. Examples include the production of ethanol (Singh et al, 1998;Kourkoutas et al, 2002), cell protein (Kim et al, 1998;Grba et al, 2002;Schultz et al, 2006), bioingredients (Belem & Lee, 1998), enzymes, such as inulinase (Rouwenhorst et al, 1988;Hensing et al, 1994Hensing et al, , 1995Passador-Gurgel et al, 1996), lactase (Rech et al, 1999;Martins et al, 2002), pectinase (Cruz-Guerrero et al, 1999), lipase (Deive et al, 2003), as well as aroma compounds (Wittmann et al, 2002;Etschmann et al, 2004), and its use as baker's yeast (Caballero et al, 1995) and as an anticholesterolemic agent (Yoshida et al, 2004).…”

Purification and characterization of a lysine aminopeptidase from Kluyveromyces marxianus

“…The presence of K. marxianus has been reported, in the last years, in dairy products [1,2], in fermented drinks [3,4], and in aged cheeses [5,6], in which it seems to play an important role in the development of the functional and sensorial features of the end products. Besides, it has been used in dairy products treatment to eliminate lactose [7], in apple juice to eliminate pectic residues [8], in the production of inulinase [9], and in biodegradation of xenobiotic agents [10]. The biochemistry and the genetics of the proteolytic system of K. marxianus have not been studied, despite its potential industrial relevance.…”