Laserfiche WebLink
B;ioovr� Page 3 1 <br /> produces-,'':bacter.ia. .common!y empl oy_' oxygenase enzymes (i . e. <br /> chem- calcginpounds.. that ,catalyze 'the, :transfer' of oxygen) , <br /> This transfer pr..ocess 'requires the :.presence of molecular . <br /> oxygen and its, availability - mus•t be-considered :as an <br /> . important' limiting. facfor =for petroleuii► degradation, When. <br /> low "to moderate concentrations :of ".oil are ,thoroughly <br /> dispersed .in 'aerobic- water; it is unikely'that .a lack of <br /> oxygen -is a i:imiting `factor. ' :However, in cases where pools <br /> M of` oil-"accumulate in :soils 'and sediments ', in regions . of - <br /> intense decompasition, .- and 'in some groundwater:, the <br /> _development- of, anoxic .,conditions can: severely_= limit"'the <br /> rate of-. (bio)degradation . . - . <br /> Mineral Nutrients <br /> = Petroleum is rich in carbon and ,.energy, but deficient in , <br /> those mineral nutrients: necessa.ry:.-for microbialgrowth <br /> -(:primarily nitrogen,'._phosphorus , -iron;- and -potassium) <br /> Consequently, petroleum degrading microorganisms must <br /> obtain _these ess:ential.-materials_ ei.sewhere"' Those projects <br /> in -which macro and micro-nutri`ent,s.-.are. careful y monitored <br /> and supplied approjii- hely_"have-_shown improved degradation I <br /> rates . ­ Nutrients are =:often supp_l led_ as a component of <br /> organic mat t-er ' (such aS--compost) or,: as custom :fo.rmulations <br /> aler <br /> of commerci " .fn l zers <br /> s - x _ <br /> :.Additional Factors <br /> •In =addition-to the above, two interes.t-ing' procesdes .can, <br /> 'and,.probably most often do;_ occur in :the degradationof <br /> petro.-1eum liydr -C 'rbon-s:' , These are :sparing 'and:- co- <br /> oxidation. <br /> co-oxidation. -For example acetate, 'an" intermediate product <br /> -in .hydrocarbon biodegradation,—has been found=`to reduce the = . <br /> utilization -o:f hexadecane �: The =basis for this sparing <br /> eff'ect .is not. weI I=defined; 'but it- certainl:y ,occurs for _ <br /> other' hydrocarbons'; as ;well . Co-oxidation is: a process in. <br /> which- com'pounds: whi-ch otherwise would not be degraded.. can <br /> be attached- by .-enzmes 3°due . to`.`the :.abilities o <br /> yf:-the" <br /> t <br /> individual microorganisms producing ^the ' enzymes -to .ut.il-ize. - <br /> other hydrocarbons: within-. the ;petro-l;eum. mixture.- The <br /> complexities -of.. petroleum compounds"_:pzovide an- excellent. <br /> ti chemical envronment .`in. whch ,ca-oxidation -can- occur, and <br /> many ,complex.�br.anched and- cyclic .hydrocarbons°'' are degraded. <br /> =as ' a .result. It has been. found°, f.oY instance; that the <br /> degradation. of hydrocarbons° within'a-'".:gasoline mixture <br /> occurred :at a" rate df,fe:rent =f.rom the degradation of .. <br /> irid-ividual compounds.: comprising the mixture.,:-'Phenomena <br /> _= <br /> such as these. do_,not .:alter. the metabolic pathways. of } <br /> degradation; -but determine=whether- .the enzymes-necessary: <br />