Novel bioanocatalysis for chromium (VI) remediation

Humphries, Andrea Claire (2005). Novel bioanocatalysis for chromium (VI) remediation. University of Birmingham. Ph.D.

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Abstract

Many industrial wastewater' s contain carcinogenic and mutagenic Cr (VI). Conversion to Cr(III) reduces toxicity. Desulfovibrio vulgaris NCIMB 8303 and Microbacterium sp. NCIMB 13776 immobilized in agar reduced Cr(VI) at initial rates of 127 and 15 nmol h\(^{-1}\) mg dry cell wf\(^{-1}\) in batch, and for 160 h in continuous-flow packed-bed columns. Similar columns containing agar-immobilized Bio-Pd(O) (Pd(II) was reduced to ceil-bound Pd(O) using growth decoupled cells of D. vulgaris) reduced Cr(VI) in excess of 1334 h. Bio-Pd(O) produced using Desulfovibrio species was catalytically superior to Bio-Pd(O) produced using Escherichia coli species. Application of enzyme kinetics to the immobilized Bio-Pd(O) system gave an apparent K\(_{m}\) value of 650 μM for batch reduction, and 430 μM for continuous-flow. Magnetic Resonance Imaging (MRI) was used to demonstrate immobilization matrix integrity, homogeneity within agar beads, and to distinguish between columns containing Cr(III) and Cr(VI), suggesting it may be possible to study Cr(VI) reduction non-invasively in vivo using MRI.
Biologically produced hydrogen was used in conjunction with resting and palladised cells of D. vulgaris for Cr(VI) reduction, and a system proposed for the concurrent treatment of industrial sugar wastes, precious metal scrap and Cr(VI).

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):