Biosynthetic Formation of Higher Alcohols by Yeast. Dependence on the Nitrogenous Nutrient Level of the Medium

Abstract

In previous investigations it has been shown that in batch fermentations the yield of higher alcohols formed biosynthetically (in the sense that yeast synthesizes the carbon skeletons needed) is mainly negatively correlated with the intial level of nitrogenous nutrients in the medium. The validity of this relationship has been established with different nitrogen sources and sugars, and at different sugar concentrations. Its causes have been studied in simple systems, using single, rapidly‐absorbed nitrogen sources, usually ammonium salts. Under such conditions it is the amount, rather than the concentration, of nitrogen source that is of importance. Yields of higher alcohols per unit weight sugar consumed are practically identical at varying nitrogen levels as long as nitrogen is available in the medium, but they increase sharply after nitrogen exhaustion, by a factor of about 2–3. However, if allowance is made for the production of valine, leucine, and isoleucine during the period when nitrogen is present, there is no rise in the total production of carbon skeletons along these pathways after the nitrogen is exhausted. On the contrary, the yields of valine‐isobutanol and isoleucine‐2‐methylbutanol skeletons per unit weight of sugar are appreciably reduced in the absence of nitrogen, whereas the yields of leucine‐3‐methylbutanol skeletons are nearly unchanged.

n-Butanol production by Saccharomyces cerevisiae from protein-rich agro-industrial by-products

“…According to the author, nitrogen deficiency, caused by the high concentration of the carbon source (i.e., higher C/N ratio), increased isobutanol production. The same behavior was observed by Äyräpää [40] when studying the influence of nitrogen source concentration on the formation of higher alcohols by Saccharomyces pastorianus.…”

Effect on the Aroma Profile of Graciano and Tempranillo Red Wines of the Application of Two Antifungal Treatments onto Vines

“…A big group of fermentative compounds are higher alcohols which are synthesized from their own precursor aminoacids by yeasts during alcoholic fermentation. There are two metabolic pathways involved in the formation of higher alcohols: the catabolic pathway of aminoacids by decarboxylation and later reduction of α-keto acids obtained by transamination of aminoacids and the anabolic pathway of aminoacids through their respective α-keto acids which are involved as intermediate in the glucidic metabolism of yeasts [27]. Chemically, higher alcohols can be aliphatic or aromatic.…”

Metabolic engineering of Corynebacterium crenatium for enhancing production of higher alcohols

“…It is well-known that the formation of higher alcohols by yeast is closely related to the metabolism of amino acids including the Ehrlich metabolic pathway21 and the biological synthesis pathway2223. The metabolic flux distribution and relevant genes involved in the formation of higher alcohols are shown in Fig.…”