skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Process development studies for the production of β-glucosidase from Aspergillus phoenicis

Abstract

This work is concerned with the production of β-glucosidase from Aspergillus phoenicis for use in the enzymatic hydrolysis of cellulose. Kinetic growth data indicate that two distinct periods of growth exist. The observed growth kinetics result from a biochemical differentiation of the filament which is independent of the substrate concentration. The optimum temperature for cell mass and β-glucosidase production was found to be 30°C. The optimum pH for β-glucosidase production is 5 and the highest specific cell growth rate was observed when the growth medium was controlled at pH 4.5. The most economical substrate was 0.75 g/l of Solka Floc, a spruce wood pulp, plus 0.25 g/l of Trichoderma viride cellulase, required because A. phoenicis does not produce all the enzymes required to solubilize cellulose. When freeze-dried A. phoenicis enzyme was added to the hydrolysis of acid treated corn stover by Tricoderma viride cellulase, the total sugar yield was increased by 4 g/l of hydrolysate over the yield of 20 g/l obtained without β-glucosidase addition. In addition, the cellobiose, which accounted for about 10% of the sugar concentration, was converted to glucose, a more widely useable product. Preliminary designs of several processes for the production of β-glucosidase were made. Themore » most economical processes were continuous production schemes. Ball milling was the most cost effective method, but the use of an elevated temperature stage was economical enough to warrant further study. The cost of production of β-glucosidase was found to be too high to justify its addition to a process for enzymatically hydrolyzing cellulose at this time.« less

Authors:
 [1];  [1]
+ Show Author Affiliations
  1. Univ. of California, Berkeley, CA (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
6631209
Alternate Identifier(s):
OSTI ID: 6631209
Report Number(s):
LBL--7867
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 60 APPLIED LIFE SCIENCES; ASPERGILLUS; CULTURE MEDIA; CELLULASES; BIOSYNTHESIS; CELLULOSE; ECONOMICS; ENZYMATIC HYDROLYSIS; ETHANOL; GLUCOSE; PH VALUE; TEMPERATURE DEPENDENCE; TRICHODERMA VIRIDE; ALCOHOLS; ALDEHYDES; CARBOHYDRATES; CHEMICAL REACTIONS; DECOMPOSITION; ENZYMES; FUNGI; HEXOSES; HYDROLASES; HYDROLYSIS; HYDROXY COMPOUNDS; LYSIS; MONOSACCHARIDES; ORGANIC COMPOUNDS; PLANTS; POLYSACCHARIDES; SACCHARIDES; SOLVOLYSIS; SYNTHESIS; TRICHODERMA 550700* -- Microbiology; 140504 -- Solar Energy Conversion-- Biomass Production & Conversion-- (-1989); 090222 -- Alcohol Fuels-- Preparation from Wastes or Biomass-- (1976-1989)

Citation Formats

Howell, Mary Jane, and Wilke, C. R. Process development studies for the production of β-glucosidase from Aspergillus phoenicis. United States: N. p., 1978. Web. doi:10.2172/6631209.
Copy to clipboard
Howell, Mary Jane, & Wilke, C. R. Process development studies for the production of β-glucosidase from Aspergillus phoenicis. United States. doi:10.2172/6631209.
Copy to clipboard
Howell, Mary Jane, and Wilke, C. R. Fri . "Process development studies for the production of β-glucosidase from Aspergillus phoenicis". United States. doi:10.2172/6631209. https://www.osti.gov/servlets/purl/6631209.
Copy to clipboard
@article{osti_6631209,
title = {Process development studies for the production of β-glucosidase from Aspergillus phoenicis},
author = {Howell, Mary Jane and Wilke, C. R.},
abstractNote = {This work is concerned with the production of β-glucosidase from Aspergillus phoenicis for use in the enzymatic hydrolysis of cellulose. Kinetic growth data indicate that two distinct periods of growth exist. The observed growth kinetics result from a biochemical differentiation of the filament which is independent of the substrate concentration. The optimum temperature for cell mass and β-glucosidase production was found to be 30°C. The optimum pH for β-glucosidase production is 5 and the highest specific cell growth rate was observed when the growth medium was controlled at pH 4.5. The most economical substrate was 0.75 g/l of Solka Floc, a spruce wood pulp, plus 0.25 g/l of Trichoderma viride cellulase, required because A. phoenicis does not produce all the enzymes required to solubilize cellulose. When freeze-dried A. phoenicis enzyme was added to the hydrolysis of acid treated corn stover by Tricoderma viride cellulase, the total sugar yield was increased by 4 g/l of hydrolysate over the yield of 20 g/l obtained without β-glucosidase addition. In addition, the cellobiose, which accounted for about 10% of the sugar concentration, was converted to glucose, a more widely useable product. Preliminary designs of several processes for the production of β-glucosidase were made. The most economical processes were continuous production schemes. Ball milling was the most cost effective method, but the use of an elevated temperature stage was economical enough to warrant further study. The cost of production of β-glucosidase was found to be too high to justify its addition to a process for enzymatically hydrolyzing cellulose at this time.},
doi = {10.2172/6631209},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Sep 01 00:00:00 EDT 1978},
month = {Fri Sep 01 00:00:00 EDT 1978}
}
Copy to clipboard
Thesis/Dissertation:
View Thesis/Dissertation (2.44 MB)
DOI:  10.2172/6631209
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this thesis or dissertation.
Save / Share:
Export Metadata
Save to My Library
You must Sign In or Create an Account in order to save documents to your library.

  • Limestone can be used more effectively as a sorbent for H 2S in high-temperature gas-cleaning applications if it is prevented from undergoing calcination. Sorption of H 2S by limestone is impeded by sintering of the product CaS layer. Sintering of CaS is catalyzed by CO 2, but is not affected by N 2 or H 2. The kinetics of CaS sintering was determined for the temperature range 750--900°C. When hydrogen sulfide is heated above 600°C in the presence of carbon dioxide elemental sulfur is formed. The rate-limiting step of elemental sulfur formation is thermal decomposition of H 2S. Part ofmore » the hydrogen thereby produced reacts with CO 2, forming CO via the water-gas-shift reaction. The equilibrium of H 2S decomposition is therefore shifted to favor the formation of elemental sulfur. The main byproduct is COS, formed by a reaction between CO 2 and H 2S that is analogous to the water-gas-shift reaction. Smaller amounts of SO 2 and CS 2 also form. Molybdenum disulfide is a strong catalyst for H 2S decomposition in the presence of CO 2. A process for recovery of sulfur from H 2S using this chemistry is as follows: Hydrogen sulfide is heated in a high-temperature reactor in the presence of CO 2 and a suitable catalyst. The primary products of the overall reaction are S 2, CO, H 2 and H 2O. Rapid quenching of the reaction mixture to roughly 600°C prevents loss Of S 2 during cooling. Carbonyl sulfide is removed from the product gas by hydrolysis back to CO 2 and H 2S. Unreacted CO 2 and H 2S are removed from the product gas and recycled to the reactor, leaving a gas consisting chiefly of H 2 and CO, which recovers the hydrogen value from the H 2S. This process is economically favorable compared to the existing sulfur-recovery technology and allows emissions of sulfur-containing gases to be controlled to very low levels.« less

  • Traditionally soymilk has been made with whole soybeans; however, there are other alternative raw ingredients for making soymilk, such as soy flour or full-fat soy flakes. US markets prefer soymilk with little or no beany flavor. modifying the process or using lipoxygenase-free soybeans can be used to achieve this. Unlike the dairy industry, fat reduction in soymilk has been done through formula modification instead of by conventional fat removal (skimming). This project reports the process optimization for solids and protein extraction, flavor improvement and fat removal in the production of 5, 8 and 12 °Brix soymilk from full fat soymore » flakes and whole soybeans using the Takai soymilk machine. Proximate analyses, and color measurement were conducted in 5, 8 and 12 °Brix soymilk. Descriptive analyses with trained panelists (n = 9) were conducted using 8 and 12 °Brix lipoxygenase-free and high protein blend soy flake soymilks. Rehydration of soy flakes is necessary to prevent agglomeration during processing and increase extractability. As the rehydration temperature increases from 15 to 50 to 85 C, the hexanal concentration was reduced. Enzyme inactivation in soy flakes milk production (measured by hexanal levels) is similar to previous reports with whole soybeans milk production; however, shorter rehydration times can be achieved with soy flakes (5 to 10 minutes) compared to whole beans (8 to 12 hours). Optimum rehydration conditions for a 5, 8 and 12 °Brix soymilk are 50 C for 5 minutes, 85 C for 5 minutes and 85 C for 10 minutes, respectively. In the flavor improvement study of soymilk, the hexanal date showed differences between undeodorized HPSF in contrast to triple null soymilk and no differences between deodorized HPSF in contrast to deodorized triple null. The panelists could not differentiate between the beany, cereal, and painty flavors. However, the panelists responded that the overall aroma of deodorized 8 °Brix triple null and HPSF soymilk are lower than the undeodorized triple null and HPSF soymilk. The triple null soymilk was perceived to be more bitter than the HPSF soymilk by the sensory panel due to oxidation on the triple null soy flakes. This oxidation may produce other aroma that was not analyzed using the GC but noticed by the panelists. The sensory evaluation results did show that the deodorizer was able to reduce the soymilk aroma in HPSF soymilk so it would be similar to triple null soymilk at 8 °Brix level. Regardless of skimming method and solids levels, the fat from the whole soybean milk was removed less efficiently than soy flake milk (7 to 30% fat extraction in contrast to 50 to 80% fat extraction respectively). In soy flake milk, less fat was removed as the % solid increases regardless of the processing method. In whole soybean milk, the fat was removed less efficiently at lower solids level milk using the commercial dairy skimmer and more efficient at lower solids level using the centrifuge-decant method. Based on the Hunter L, a, b measurement, the color of the reduced fat soy flake milk yielded a darker, greener and less yellow colored milk than whole soymilk (α < 0.05), whereas no differences were noticed in reduced fat soybean milk (α < 0.05). Color comparison of whole and skim cow's milk showed the same the same trend as in the soymilk.« less

  • A process for the removal of hydrogen sulfide from coal-derived gas streams has been developed. The basis for the process is the absorption of H/sub 2/S into a polar organic solvent where it is reacted with dissolved sulfur dioxide to form elemental sulfur. After sulfur is crystallized from solution, the solvent is stripped to remove dissolved gases and water formed by the reaction. The SO/sub 2/ is generated by burning a portion of the sulfur in a furnace where the heat of combustion is used to generate high pressure steam. The SO/sub 2/ is absorbed into part of the leanmore » solvent to form the solution necessary for the first step. The kinetics of the reaction between H/sub 2/S and SO/sub 2/ dissolved in mixtures of N,N-Dimethylaniline (DMA)/Diethylene Glycol Monomethyl Ether and DMA/Triethylene Glycol Dimethyl Ether was studied by following the temperature rise in an adiabatic calorimeter. The reaction provides a foundation for the development of a process for removing H/sub 2/S from a fuel gas made by gasifying high-sulfur coal. A computer simulation was written to permit rapid analysis of potential process alternatives. Calculations in the simulation were performed in unit sequential fashion with convergence accelerated using Wegstein's method. Modifications were made to standard engineering unit models to account for the presence of the reaction between H/sub 2/S and SO/sub 2/. A flowsheet and detailed heat and material balances for a process for the reduction of the H/sub 2/S content of a gasified coal stream from 60,000 to 1 ppM are presented.« less

  • Conventional natural gas processing schemes are based on the sequential removal of sulfur compounds, water and hydrocarbon liquids with each processing step requiring a different process. The processing scheme proposed here removes all three in a single absorption step and is an integrated arrangement based on the University of California, Berkeley Sulfur Recovery Process (UCBSRP) technology. This processing scheme promises both reduced capital and operating costs. High purity sulfur product and natural gas liquids are produced and all exit streams contain less than 1 ppM of either hydrogen sulfide or sulfur dioxide. The UCBSRP technology is based on absorption ofmore » hydrogen sulfide and sulfur dioxide by a polar organic solvent. Certain classes of polyglycol ethers are suitable solvents for hydrogen sulfide, sulfur dioxide and light hydrocarbon gases. These solvents are also miscible with water. Hydrogen sulfide reacts with sulfur dioxide (generated by burning sulfur) in the liquid phase to form elemental sulfur and water. Sulfur is partially miscible in the solvent. Information on the solubility of hydrocarbon and acid gases is required for these organic solvents. Furthermore, knowing the solubility of elemental sulfur in these solvents is also necessary. The experimental portion of this work is concerned with the measurement of these solubilities as a function of temperature, solvent composition and water content. Solubility data were collected for hydrogen sulfide, sulfur dioxide, carbon dioxide, propane, and butane in a variety of mono- and diethers of polyethylene glycol. Solubility data for sulfur in these solvents were also collected. Correlations were developed for both gas and sulfur solubilities.« less