Biological effects of high molecular weight lignin derivatives.

A number of high molecular weight (HMW) lignin derivatives possessing varied chemical properties were screened for their biological effects in order to obtain more information on the possible structural features of HMW lignin-related effects. The studied compounds were both commercial and in-house extracted lignin derivatives. Bioassays used include reverse electron transport (RET), Vibrio fischeri, Daphnia magna, and juvenile rainbow trout (Oncorhynchus mykiss) hepatocytes. The studied lignin derivatives inhibited the in vitro systems and luminescence of V. fischeri bacteria to some extent-daphnids were not affected. It seems that, at least in the RET assay, certain pH-dependent functional groups in lignin may be of importance regarding the biological effects.