Salt, EDTA, and pH effects on rheological behavior of mold suspensions

1992-11
Dik, Tunay
Bozoğlu, T. Faruk
Show full item record
665
views
0
downloads
The effects of surface properties on the rheological behavior of Aspergillus niger suspensions were studied at pH 2-7, with the addition of 0-0.10 m NaH2PO4, NaCl, CaCl2, AlCl3, and EDTA at shear rates of 0-21.6 s-1. The structural network concept was used to discuss the consequences of cell-cell interactions on the rheological behavior. Analysis of the data indicated that the suspensions containing CaCl2 nearly always had the smallest shear stress at all the pH values, indicating that, unlike with the yeast suspensions, Ca2+ does not contribute to the specific bonding of the mold cells. At low pH and salt concentrations, NaH2PO4 was better than AlCl3 for promoting bond formation between the cells. When either the salt concentration or the pH was increased, AlCl3 became a better bond formation agent than NaH2PO4. EDTA removes the charged groups from surfaces and encourages cell-cell contact via hydrophobic interactions. The shear stress and consistency index increased while the flow behavior index decreased with EDTA concentration.
Biotechnology, Applied Microbiology and Biotechnology, Biochemistry, Mold suspension, network structure, rheological model, surface chemistry
https://hdl.handle.net/11511/88531
Enzyme and Microbial Technology
Technical Vocational School of Higher Education, Article

Suggestions

Kinetic analyses of the effects of temperature and light intensity on growth, hydrogenm production and organic acid utilization by rhodobacter capsulatus
Sevinç, Pelin; Gündüz, Ufuk; Department of Biotechnology (2010)
Effects of temperature and light intensity on photofermentative hydrogen production by Rhodobacter capsulatus DSM1710 by use of acetic and lactic acids as substrates were studied. Experiments were conducted at 20, 30 and 38oC incubator temperatures under light intensities in the 1500 – 7000 lux range. pH of the medium and quantity of hydrogen forming together with quantity of biomass, and concentrations of acetic, lactic, formic, butyric and propionic acids in the medium were determined periodically. Growth...
Substrate interactions during the biodegradation of benzene, toluene and phenol mixtures
Abu Hamed, T; Bayraktar, E; Mehmetoglu, T; Mehmetoglu, U (Elsevier BV, 2003-09-30)
Benzene, toluene and phenol were degraded completely at high initial concentrations by Pseudomonas putida F I ATCC 700007. Two hundred and fifty milligram per litre benzene, 225 mg/l toluene and 200 mg/l phenol were degraded individually in 19, 14 and 3 5 h, respectively. The biodegradation times increased on increasing the substrate concentration. The maximum biodegradation rates were 149 mg benzene/g dry cell h for 60 mg/l benzene, 44 mg toluene/g dry cell h for 110 mg/l toluene and 102 mg phenol/g dry ce...
SETTLING KINETICS OF CHAMPAGNE YEAST
ARIKAN, O; OZILGEN, M (Elsevier BV, 1992-09-01)
Settling kinetics of champagne yeast were studied with 0.01, 0.05, and 0.10 m NaCl, CaCl2, AlCl3, and 1.00 +/- 0.01 OD660 (optical density at 660 nm) initial yeast concentration at pH 1. In the suspensions with 0.01 M NaCl, the pH of the medium varied between 1 and 3, and the initial yeast concentration changed between 0.74 and 1.25 OD660. Analysis of the data showed that the settling phenomena occurred in two steps: (i) establishment of the diffuse double layer to overcome repulsion, hence achievement of c...
Oxygen transfer effects in serine alkaline protease fermentation by Bacillus licheniformis: Use of citric acid as the carbon source
Çalık, Pınar (Elsevier BV, 1998-12-01)
The effects of oxygen transfer on serine alkaline protease (SAP) production by Bacillus licheniformis on a defined medium with C-c = 9.0 kg m(-3) citric acid as sole carbon source were investigated in 3.5 dm(3) batch bioreactor systems. The concentrations of the product (SAP) and by-products, i.e., neutral protease, amylase, amino acids, and organic acids were determined in addition to SAP activities. Ar Q(o)/V = 1 vvm airflow rate, the effect of agitation rate on DO concentration, pH, product, and by-produ...
Preparation of cross-linked tyrosinase aggregates
Aytar, Burcu Selin; Bakir, Ufuk (Elsevier BV, 2008-02-01)
Tyrosinase from mushroom was immobilized as a cross-linked enzyme aggregate (CLEA) via precipitation with ammonium sulfate and cross-linking with glutaraldehyde. The effects of precipitation and cross-linking on CLEA activity were investigated and the immobilized tyrosinase was characterized. Sixty percent ammonium sulfate saturation and 2% glutaraldehyde were used; a 3-h cross-linking reaction at room temperature, at pH 7.0 was performed; particle sizes of the aggregates were reduced; consequently, 100% ac...
Citation Formats
T. Dik and T. F. Bozoğlu, “Salt, EDTA, and pH effects on rheological behavior of mold suspensions,” Enzyme and Microbial Technology, pp. 944–948, 1992, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/88531.
METU IIS - Integrated Information Service open@metu.edu.tr