Environmental Fate and Transport of Solvent-Stabilizer Compounds - Environmental Investigation and Remediation - page 159

TABLE 3.19
Kinetics of 1,4-Dioxane and 1,3-Dioxolane Biodegradation

Maximum
Growth Rate
(μ max /h)

Half-Saturation
Constant, K s
(mg/L)

Temperature
(°C)

Yield
(mg/mg)

Specifi c Rate,
r / X [mg/(g h)]

Culture References

CB1190 30 0.0230 — — 9.9 at 500 ppm Adamus et al. (1995)

Mixed 25 0.0100 0.33 13.51 27 at 100 ppm Grady et al. (1997)

Mixed 35 0.0430 0.64 1.04 66 at 100 ppm Grady et al. (1997)

Mixed — 0.141 0.12 9.9 0.12 Grady et al. (1997)

Industrial activated
sludge

— 0.062 0.44 1.65 — Sock (1993) (cited in

Zenker et al., 2002)

Nocardioform
actinomycete

30 0.033 0.02 — 1.98 Parales et al. (1994)

Industrial activated
sludge

— 0.0053 0.22 182 — Roy et al. (1995)

Pseudonocardia
strain ENV478

30 21 at 100 μg/L

DX

Vainberg et al. (2006)

Mixed 30 0.083 0.75 Zenker et al. (2000)

13 ± 7.6 0.05 ± 0.003 at

200 ppm

Pseudonocardia
dioxanivorans
CB1190

30 0.10 0.09 Mahendra and

Alvarez-Cohen
(2006)

160 ± 44 1.1 ± 0.008 at

100 ppm

Pseudonocardia
benzenivorans B5

30 0.07 0.03 330 ± 82 0.1 ± 0.006 at

100 ppm

Mahendra and
Alvarez-Cohen
(2006)

Amycolata sp.
CB1190

~24 — 0.01 — Kelley et al. (2001)

0.92 ± 0.29 at
100 ppm

Pseudonocardia
strain ENV478

30 — — — 19 Vainberg et al. (2006)

Source: From Grady, C.P.L., Jr., Sock, S.M., and Cowan, R.M., 1997, In: G.S. Sayler, J. Sanseverino, and K.L. Davis (Eds),
Biotechnology in the Sustainable Environment . New York: Plenum Press. With permission.
Note: The last entry, for Pseudonocardia Strain ENV478, is for biodegradation of 1,3-dioxolane. The other entries are for
biodegradation of 1,4-dioxane.

Fungal biomass increases through hyphal lengthening * and branching instead of by the splitting
and doubling (binary i ssion) mechanism used by bacteria. Fungal growth occurs primarily at the
ends of the i laments, which grow at a constant rate. Because fungi and other i lamentous organisms
such as actinomycetes may grow radially in three dimensions, growth may follow cubic kinetics;
however, growth in the subsurface is constrained by the porous matrix.
The pathway for aerobic degradation of 1,4-dioxane parallels that of THF, which involves oxyge-
nase-mediated hydroxylation of the carbon present in the no. 2 position on the dioxane ring and its
subsequent dehydrogenation to form the lactone ring. Hydroxylation is any process that introduces one
or more hydroxyl groups (-OH) into a compound (or radical), thereby oxidizing it. In biochemistry,
hydroxylation reactions are often facilitated by enzymes called hydroxylases. A lactone is a cyclic
ester. After opening the lactone ring, intermediary metabolism pathways may begin (Zenker, 2006).

* A hypha (plural hyphae) is a long, branching i lamentous cell of a fungus and also of unrelated Actinobacteria . In fungi,
hyphal lengthening is the main mode of growth.