No abstract

Dicyclopentadiene (DCPD) is formed during the pyrolysis of alkanes to produce olefins suitable for manufacturing synthetic polymers. DCPD has an irritating odor with a 5 ppb detection level that provides the impetus for remediation efforts. One method of destroying odors is to alter the structure of the chemical. This can be accomplished by biological oxidation using microorganisms. Field studies at two sites, where DCPD was a soil contaminant, indicated that biodegradation contributed significantly to DCPD removal. DCPD degradation was stimulated by decreasing bulk soil density and adding nitrogen and phosphorous nutrients. The presence of other easier degradable aromatic hydrocarbons may also be beneficial, suggesting that the process is cometabolic.

No abstract

A purified microbial isolate, identified as a strain of Rhodococcus sp., metabolized indene primarily to iso quinoline and lesser amounts of indandiol and indanone. Isoquinoline production was dependent on the presence of microbial culture, indene, and ammonium ions as the source of nitrogen in the molecule. The ability to produce isoquinoline was induced by growth on benzene or naphthalene and by the presence of indene itself. The culture produced compounds tentatively identified as 3-methylisoquinoline and 3-ethylisoquinoline from 2-methylindene and from 2-ethylindene, respectively. Deuterated indene was converted to deuterated isoquinoline, deuterated indanone, and deuterated indandiol. Experiments with [15N]ammonium nitrate and ammonium [15N]nitrate confirmed ammonium as the source of nitrogen in the isoquinoline products.

A steroid-binding protein, identified in the supernatant generated when membrane vesicles of Pseudomonas testosteroni are produced and harvested by centrifugation, has been purified 49-fold to homogeneity. It has a molecular weight of 30 000-35 000 and it specifically binds the C19 steroids dihydrotestosterone, testosterone, and androstenedione. It is a basic protein with an isoelectric point at pH 7.3. Binding of testosterone exhibited normal saturation kinetics with an affinity constant, Kd, of 3.9 X 10(-8) M. Binding was inhibited by divalent cations, but the sulfhydryl reagents dithiothreitol and mercaptoethanol did not affect activity. It is suggested that this and other membrane-associated steroid-binding proteins concentrate the steroid at the membrane surface before it is transported into the cytoplasm of P. testosteroni.