A Soluble Methane Monooxygenase-Constitutive Mutant Strain of Methylosinus Trichosporium OB3b, Strain PP358, Was Grown with Methanol as the Carbon Source, and the Kinetics of Trichloroethylene (TCE) Degradation Were Determined. PP358 Exhibited High TCE Degradation Rates under Both Oxygen- and Carbon-Limiting Conditions. the Optimal Pseudo First-Order Rate Constant for TCE Was Comparable to the Values Measured for Cells Grown with Methane. We Found that Growth under Oxygen-Limiting Conditions Results in Increased Accumulation of Polyhydroxybutyrate, Which in Turn Correlates with Higher Transformation Capacities for TCE. It Was Also Shown that Methanol Inhibits TCE Degradation Only at High Concentrations. Thus, Methanol-Grown Cultures of PP358 Represent an Efficient System for the Biodegradation of Chlorinated Hydrocarbons.