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Title: Optimization of batch alcoholic fermentation of glucose syrup substrate. [Box-Wilson central composite design]

Abstract

The quantitative effects of substrate concentration, yeast concentration, and nutrient supplementation on ethanol content, fermentation time, and ethanol productivity were investigated in a Box-Wilson central composite design experiment, consisting of five levels of each variable. The highest ethanol productivity of about 21 g EtOH/liter hr was obtained at low substrate concentration (i.e., 12/degree/Brix), low alcohol content (i.e., 6% by weight), high yeast concentration (i.e., 4.4%), and high supplementation of yeast extract (i.e., 6% by weight), high yeast concentration (i.e., 4.4%), and high supplementation of yeast extract (i.e., 2.8%). Productivity of this magnitude is substantially higher than that of the traditional batch fermentation or fed-batch fermentation. It is comparable to the results of continuous fermentation but lower than those of vacuum fermentation. Optimal conditions for maximal ethanol productivity can be established by a multiple regression analysis technique and by plotting the contours of constant response to conform to the constraints of individual operations. 12 refs.

Authors:
Publication Date:
Research Org.:
Univers Foods Corp, Milwaukee, Wis, USA
OSTI Identifier:
5135443
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biotechnol. Bioeng.; (United States); Journal Volume: 23:8
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; ETHANOL; PRODUCTION; FERMENTATION; OPTIMIZATION; GLUCOSE; SUBSTRATES; YEASTS; ALCOHOLS; ALDEHYDES; BIOCONVERSION; CARBOHYDRATES; FUNGI; HEXOSES; HYDROXY COMPOUNDS; MICROORGANISMS; MONOSACCHARIDES; ORGANIC COMPOUNDS; PLANTS; SACCHARIDES; 090222* - Alcohol Fuels- Preparation from Wastes or Biomass- (1976-1989); 140504 - Solar Energy Conversion- Biomass Production & Conversion- (-1989)

Citation Formats

Chen, S.L.. Optimization of batch alcoholic fermentation of glucose syrup substrate. [Box-Wilson central composite design]. United States: N. p., 1981. Web. doi:10.1002/bit.260230810.
Chen, S.L.. Optimization of batch alcoholic fermentation of glucose syrup substrate. [Box-Wilson central composite design]. United States. doi:10.1002/bit.260230810.
Chen, S.L.. Sat . "Optimization of batch alcoholic fermentation of glucose syrup substrate. [Box-Wilson central composite design]". United States. doi:10.1002/bit.260230810.
@article{osti_5135443,
title = {Optimization of batch alcoholic fermentation of glucose syrup substrate. [Box-Wilson central composite design]},
author = {Chen, S.L.},
abstractNote = {The quantitative effects of substrate concentration, yeast concentration, and nutrient supplementation on ethanol content, fermentation time, and ethanol productivity were investigated in a Box-Wilson central composite design experiment, consisting of five levels of each variable. The highest ethanol productivity of about 21 g EtOH/liter hr was obtained at low substrate concentration (i.e., 12/degree/Brix), low alcohol content (i.e., 6% by weight), high yeast concentration (i.e., 4.4%), and high supplementation of yeast extract (i.e., 6% by weight), high yeast concentration (i.e., 4.4%), and high supplementation of yeast extract (i.e., 2.8%). Productivity of this magnitude is substantially higher than that of the traditional batch fermentation or fed-batch fermentation. It is comparable to the results of continuous fermentation but lower than those of vacuum fermentation. Optimal conditions for maximal ethanol productivity can be established by a multiple regression analysis technique and by plotting the contours of constant response to conform to the constraints of individual operations. 12 refs.},
doi = {10.1002/bit.260230810},
journal = {Biotechnol. Bioeng.; (United States)},
number = ,
volume = 23:8,
place = {United States},
year = {Sat Aug 01 00:00:00 EDT 1981},
month = {Sat Aug 01 00:00:00 EDT 1981}
}
  • The quantitative effects of substrate concentration, yeast concentration, and nutrient supplementation on ethanol content, fermentation time, and ethanol productivity were investigated in a Box-Wilson central composite design experiment, consisting of five levels of each variable. High substrate concentration, up to 30 degrees Brix, resulted in higher ethanol content (i.e., up to 15.7% w/v or 19.6% v/v) but longer fermentation time and hence lower ethanol productivity. Increasing yeast concentration, on the other hand, resulted in shorter fermentation time and higher ethanol productivity. Higher levels of nutrient supplementation generally led to shorter fermentation time and higher productivity. The highest ethanol productivity ofmore » about 21 g ethanol h was obtained at low substrate concentration (i.e., 12 degrees Brix), low alcohol content (i.e., 6% by weight), high yeast concentration (i.e., 4.4%), and high supplementation of yeast extract (i.e., 2.8%). Productivity of this magnitude is substantially higher than that of the traditional batch fermentation or fed-batch fermentation. It is comparable to the results of continuous fermentation but lower than those of vacuum fermentation. Optimal conditions for maximal ethanol productivity can be established by a multiple regression analysis technique and by plotting the contours of constant response to conform to the constraints of individual operations. (Refs. 12).« less
  • Evaporative loss of ethanol during batch alcoholic fermentation has been modeled, employing modern concepts of kinetics and stoichiometry and the best available phase equilibrium thermodynamic data. Theoretical results demonstrate that loss is proportional to the second power of the sugar concentration utilized and that the logarithm of loss is proportional to reciprocal absolute temperature. Good agreement is demonstrated among the theory, the numerical model, and the literature results. A master correlation for predicting ethanol loss is presented.
  • In continuous alcoholic fermentation a strong correlation between CO/sub 2/ evolution rate and ethanol production rate at stationary state is observed. Earlier studies have shown that yields could be increased if substrate inhibition is removed. Productivity decreases drastically at high glucose concentrations with increasing ethanol concentration in the culture medium. In order to achieve higher final ethanol concentrations, substrate concentration should be kept under inhibition limits, e.g., under 100 g/L during all the fermentation time. The Fed-batch approach, therefore, seems a good technique to reach higher productivity. Substrate feeding is delicate in fed-batch operation. Step-wise feeding can either cause excessmore » of substrate or substrate limitation. Yeast alcoholic fermentation does not need such sophisticated control as those generally proposed in the literature. In this communication, a simple device is described which was accurate enough to keep substrate concentration in the limits of 20 +/- 2 g/L.« less
  • The effect of ethanol and sugars on rates of fermentation was studied. A strain of Candida pseudotropicalis was used. The specific rate of fermentation was determined by using the Warburg manometer. The effect of ethanol was formulated as an exponential function of ethanol concentration, but the empirical constant was different when glucose or lactose was used as a substrate. The effects of both ethanol and substrate were formulated. It was demonstrated that when lactose and glucose were present in the medium with a small amount of alcohol, a synergistic effect on the rate of fermentation appeared. This phenomenon considerably limitsmore » the rate of fermentation.« less