The influence of nitrogen and biotin interactions on the performance of Saccharomyces in alcoholic fermentations.
OBJECTIVE
To study the impact of assimilable nitrogen, biotin and their interaction on growth, fermentation rate and volatile formation by Saccharomyces.


RESULTS
Fermentations of synthetic grape juice media were conducted in a factorial design with yeast assimilable nitrogen (YAN) (60 or 250 mg l(-1)) and biotin (0, 1 or 10 microg l(-1)) as variables. All media contained 240 g l(-1) glucose + fructose (1 : 1) and were fermented using biotin-depleted Saccharomyces cerevisiae strains EC1118 or UCD 522. Both strains exhibited weak growth and sluggish fermentation rates without biotin. Increased nitrogen concentration resulted in higher maximum fermentation rates, while adjusting biotin from 1 to 10 microg l(-1) had no effect. Nitrogen x biotin interactions influenced fermentation time, production of higher alcohols and hydrogen sulfide (H(2)S). Maximum H(2)S production occurred in the medium containing 60 mg l(-1) YAN and 1 microg l(-1) biotin.


CONCLUSIONS
Nitrogen x biotin interactions affect fermentation time and volatile production by Saccharomyces depending on strain. Biotin concentrations sufficient to complete fermentation may affect the organoleptic impact of wine.


CONCLUSIONS
This study demonstrates the necessity to consider nutrient interactions when diagnosing problem fermentations.
Bohlscheid
J C
JC
Department of Food Science and Human Nutrition, Washington State University, Pullman, WA 99164-6376, USA. jbohlscheid@wsu.edu
Fellman
J K
JK
Wang
X D
XD
Ansen
D
D
Edwards
C G
CG
D000438:Alcohols / Q000378:metabolism*; D001710:Biotin / Q000378:metabolism / Q000494:pharmacology*; D002208:Caproates / Q000032:analysis / Q000378:metabolism; D002210:Caprylates / Q000032:analysis / Q000378:metabolism; D005285:Fermentation; D005516:Food Microbiology; D006862:Hydrogen Sulfide / Q000032:analysis / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D027843:Vitis; D014835:Volatilization; D014920:Wine
D000438:Alcohols; D002208:Caproates; D002210:Caprylates; D001710:Biotin; C079237:ethyl hexanoate; D009584:Nitrogen; C031492:octanoic acid; D006862:Hydrogen Sulfide