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Lactic acid fermentations were performed with plastic composite-support (PCS) discs in solvent saturated media with Lactobacillus casei subsp rhamnosus (ATTC 11443). The PCS discs contained 50% (wt/wt) polypropylene, 35% (wt/wt) ground soybean hulls, 5% (wt/wt) yeast extract, 5% (wt/wt) soybean flour, and 5% (wt/wt) bovine albumin. Bioassays were performed by growing L. casei in solvent saturated media after soaking PCS discs. Eighteen different solvent and carrier combinations were evaluated. Overall, L. casei biofilm fermentation demonstrated the same lactic acid production in solvent saturated medium as suspended-cells in medium without solvents (control). To evaluate PCS solvent detoxifying properties, a bioassays was developed. When solvent saturated medium in consecutive equal volumes was exposed to PCS, both media demonstrated lactic acid fermentation equal to the control. Furthermore, iso-octane, TBP and Span 80 were optimized for recovery as 91, 5, and 4% (v/v), respectively, with 1:1 ratio of 1.2 M Na2CO3 stripping solution. Also, recovery by emulsion liquid extraction in the hollow fiber contactor was minimal due to low recovery at pH 5.0 and incompatibility of the solvent and hollow fiber material. These results suggest that PCS biofilm reactors can benefit lactic acid fermentation by eliminating the toxic effect from solvent leakage into the fermentation medium from liquid-liquid extractive integrated fermentations.