can be simultaneously acclimated to other compounds, and

that a microbial population can metabolize several compounds

at the same time. However, Shimp and Pfaender (1985a,

1985b) reported the organic substances to which the

microorganisms have already been exposed can significantly

influence the ability of microorganisms to degrade other

organic compounds. They observed that exposure to amino

acids, carbohydrates or fatty acids enhances the ability of

microorganisms to degrade certain phenolic compounds while

exposure to humic materials had a negative effect.

 More than 25 species of microorganisms were reported

 capable of degrading PCP (Engelhardt et al., 1986). They

 were isolated from soils, municipal wastewater sludges,

 surface waters and groundwaters. Among these microorganisms

 Arthrobacter, Trichoderma virgatum, Flavobacterium sp., and

 Pseudomonas were most reported (Brown et al., 1986; Crosby,

 1981; Edgehill and Finn, 1983; Kaufman, 1978; Mikesell and

 Boyd, 1985; Stanlake and Finn, 1982; Steiert et al., 1987;

 Suzuki, 1975; and Suzuki, 1977).


 Nutrients. Microorganisms need nitrogen, phosphorus

and some trace minerals for incorporation into biomass, so

the availability of these nutrients is critical to

biodegradation. A general formula for microorganism

composition was proposed as C60H87023 12P (Benefield and

Randall, 1980). This formula reveals a C:N:P ratio of

23:5.3:1 in microorganism cells. However, optimal C:N and

C:P ratios for marine oil-degrading microorganisms were