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Title: Utilization of immobilized B-glucosidase in the enzymatic hydrolysis of cellulose

Thesis/Dissertation ·
DOI:https://doi.org/10.2172/5974651· OSTI ID:5974651
 [1];  [1]
  1. Univ. of California, Berkeley, CA (United States)

β-glucosidase obtained from Aspergillus phoenicis was immobilized onto phenol formaldehyde resin using glutaraldehyde as a fixing agent, and kinetic characteristics such as pH optimum, temperature stability and Michaelis-Menton constants were determined. Three experiments were performed where a batch hydrolysis of a cellulosic source was carried out with a recycle stream through an immobilized β-glucosidase column in order to continuously remove cellobiose. The first two experiments using pretreated corn stover as the substrate showed no increase in hydrolysis over that of a control system, presumably because the cellobiose production was too low for cellobiose inhibition to occur. The third experiment, using Solka Floc as the substrate, which produced as high as 8.8 grams per liter of cellobiose, showed only a slight increase in soluble sugar production over that of the control system. Since the current process indicates the use of corn stover or a similar substrate, it does not appear useful to include an immobilized enzyme reactor in this manner. Since the fermentation part of the process cannot use cellobiose to produce ethanol, the use of the immobilized β-glucosidase reactor to convert the cellobiose to glucose may have economic significance by increasing the ethanol yield in this fashion. A computer program was produced in order to simulate a fixed-bed reactor with diffusion limitations and to determine the cost per pound of glucose for a given reactor design. Use of the immobilized enzyme system results in a savings of 0.53 cents per pound of glucose, which results in a corresponding savings of 7.2 cents per gallon of ethanol upon subsequent fermentation of the hydrolyzate.

Research Organization:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
5974651
Report Number(s):
LBL-7857
Resource Relation:
Other Information: Thesis
Country of Publication:
United States
Language:
English