Understanding Problem Fermentations – A Review

Malherbe, Sulette; Bauer, Florian F.; Toit, Maret du

doi:10.21548/28-2-1471

Cited by 30 publications

(33 citation statements)

References 224 publications

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“…There are several criteria to consider when it comes to selection of commercial S. cerevisiae starter cultures (Degré, 1993). These are especially important for the prevention of stuck or sluggish fermentations (Malherbe et al, 2007), which create an environment for any form of microbial spoilage to occur. The specific aspect of wine yeasts relating to Brettanomyces/Dekkera produced off-flavours revolves around their ability to produce vinylphenols via the decarboxylation of cinnamates (Clausen et al, 1994).…”

Section: Preventative Measures To Considermentioning

confidence: 99%

Significance of Brettanomyces and Dekkera during Winemaking: A Synoptic Review

Oelofse

Pretorius

Toit

2016

SAJEV

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Wine comprises a complex microbial ecology of opportunistic microorganisms, some of which could potentially induce spoilage and result in consequent economic losses under uncontrolled conditions. Yeasts of the genus Brettanomyces, or its teleomorph Dekkera, have been indicated to affect the chemical composition of the must and wine by producing various metabolites that are detrimental to the organoleptic properties of the final product. These yeasts can persist throughout the harsh winemaking process and have in recent years become a major oenological concern worldwide. This literature review summarises the main research focus areas on yeasts of the genera Brettanomyces and Dekkera in wine. Specific attention is given to the spoilage compounds produced, the methods of detection and isolation from the winemaking environment and the factors for controlling and managing Brettanomyces spoilage.

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Section: Preventative Measures To Considermentioning

confidence: 99%

Significance of Brettanomyces and Dekkera during Winemaking: A Synoptic Review

Oelofse

Pretorius

Toit

2016

SAJEV

Self Cite

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“…Apart from carbon feedstock, nitrogen is another significant nutritional element needed for active microbial growth in the fermentation of most targeted bioactive compounds [3]. Nitrogen deficiency was responsible for the significant reduction in ethanol yield reported by Malherbe, et al [4]; however, it is the most costly growth media among other components during fermentation [5,6]. Saccharomyces cerevisiae is commonly used for industrial production of bioethanol because of its ability to produce high ethanol concentrations, its low cost, and its easy availability [5,7].…”

Section: Introductionmentioning

confidence: 99%

Optimization of Corn Steep Liquor Dosage and Other Fermentation Parameters for Ethanol Production by Saccharomyces cerevisiae Type 1 and Anchor Instant Yeast

2018

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Abstract:Bioethanol production has seen an increasing trend in research recently, with a focus on increasing its economic viability. The aim of this study is to develop a low-cost fermentation medium with a minimum of redundant nutritional supplements, thereby minimizing the costs associated with nutritional supplements and seed production. Corn steep liquor (CSL) in glucose fermentation by Saccharomyces Type 1 (ST1) strain and Anchor Instant Yeast (AIY), which are low-cost media, is used as a replacement for yeast extract (YE). The fermentation process parameters were optimized using artificial neural networks (ANN) and the response surface method (RSM). The study shows that for CSL, maximum average ethanol concentrations of 41.92 and 45.16 g/L, representing 82% and 88% of the theoretical yield, were obtained after 36 h of fermentation in a shake flask for ST1 and AIY, respectively. For YE, ethanol concentrations equivalent to 86% and 88% of theoretical yield were obtained with ST1 and AIY, respectively after 48 h. Although ANN better predicted the responses compared to RSM, optimum conditions were better predicted by RSM. This study shows that corn steep liquor is an inexpensive potential nutrient that may have significant cost implications for commercial ethanol production.

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“…Different factors have an influence on this situation, e.g. viticultural treatments, harvest conditions, pH, temperature, O 2 concentration, nutrient deficiencies (nitrogen, sugar, vitamins, minerals), glucose/fructose ratio and inhibitory substances (fungicides, killer toxins) (Gafner & Schütz, 1996;Alexandre & Charpentier, 1998;Malherbe et al, 2007;Berthels et al, 2008). Although these factors are known, the problem cannot always be solved by the application of classical measures (e.g.…”

Section: Introductionmentioning

confidence: 99%