期刊
CHEMICAL ENGINEERING JOURNAL
卷 259, 期 -, 页码 574-580出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.cej.2014.07.130
关键词
Bioremediation; Encapsulation; Whole-cell biocatalyst; Silica gel; AtzA; Atrazine
资金
- NSF-IIP/PFI Grant [1237754]
- NSF-CAREER award [0644784]
- Syngenta Crop Protection and MnDrive fellowship
- BioTechnology Institute in University of Minnesota
- Div Of Chem, Bioeng, Env, & Transp Sys
- Directorate For Engineering [0644784] Funding Source: National Science Foundation
- Div Of Industrial Innovation & Partnersh
- Directorate For Engineering [1237754] Funding Source: National Science Foundation
In this study, a 3-step design and optimization method is presented for a bioremediation system utilizing silica gel encapsulated whole-cell biocatalyst. Characterization experiments were conducted to determine the parameters of a steady state reaction/diffusion model for encapsulated AtzA biocatalyst that was subsequently verified experimentally. Dimensionless numbers governing the reaction rate, the Thiele modulus (Phi) and effectiveness factor (eta), were evaluated based on the design parameters of the material, rho (cell loading density) and L-c (characteristic length). Mechanical properties of the gel were determined as a function of rho. Optimal values for rho and L-c were determined for a case study, based on biocatalytic performance, mechanical properties and cost. It was found that free biocatalyst reaction kinetics are first order with K-free = 7.38 x 10(-2) s(-1)/(g cells/mL) and diffusivity of atrazine in the gel increases with rho, from 3.51 x 10(-4) mm(2)/s up to 6.93 x 10(-4) mm(2)/s. Modeling results showed that similar to 20% of activity was lost during encapsulation. Diffusion limitations became significant (Phi > 1) when L-c exceeded 0.1-0.3 mm. The optimal catalyst radius and cell loading density were determined to be L-c = 0.2 mm and rho = 0.11 g cells/mL gel, for an atrazine bioremediation setup with a desired effluent <3 ppb. (C) 2014 Elsevier B.V. All rights reserved.
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