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KINETIC ANALYSIS OF FURFURAL INHIBITION ON POTENTIAL ETHANOL PRODUCING WILD STRAIN OF Saccharomyces cerevisiae

materials for different biotechnological processes [1, 2]. Pre-treatment of such materials is necessary due to their complex structure. With desirable products formed during pretreatment as glucose and xylose for example [1] a variety of undesirable by products are formed as organic acids and aromatic compounds (eg. furfural, formic acid, hidroxymetil furfural, levulinic acid, acetic acid)[3]. Those compounds have inhibitory effect on selected microorganism and on bioprocess efficiency [1, 4]. Origin of inhibitors can be categorized in three notable groups. First group are inhibitors present in lignocellulosic structure. Compounds as aldehydes and phenols are created during depolymerization of lignin. Acids as acetic, formic, galacturonic are formed during degradation of hemicellulose [4]. Second group of inhibitors are compounds that are formed during degradation of lignocellulosic materials. In the structure of lignin, generally they are present as non-inhibitors (pentose and hexose sugars). Under high temperature and acidic conditions, pentose sugars are degraded to furfural (furan 2- carbaldehyde) and hexose sugars to 5- hydroxymethyl furfural. Also 5- hydroxymethyl furfural can be degraded to levulinic acid and formic acid [3, 4, 5]. Third group of inhibitors are compounds present on lignocellulosic materials and are not integral part of materials itself. Most common are nitrogen and sulphur chemical compounds, heavy metals and different pesticides or other chemicals used in agriculture [3, 4, 5]. Furfural and hydroxymethyl furfural are two most important inhibitors that are created during lignocellulosic pre-treatment. Influence of furans (furfural and hydroximethylfurfural) on the biomass growth and activity can be used as an inhibition indicator for other compounds present in hydrolysates too [6, 7]. Set of experiments were carried out to investigate the inhibitory effect of furfural on the growth and ethanol production with wild strain Saccharomyces cerevisiae. Selected microorganism is potential ethanol producer from hydrolysates obtained with weak acid pre- treatment of lignocellulosic materials as wheat straw.

furfural, yeast S. cerevisiae, ethanol production, kinetic analysis

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