MICROBIAL-DEGRADATION OF CHLOROLIGNINS

Sulfate pulping and conventional bleaching of spruce wood, which had been labeled with **1**4C in the lignin component, gave rise to **1**4C-labeled chlorolignins. High relative molecular mass fractions of both the chlorination (C) and alkali extraction (E) stages were obtained by ultrafiltration (cutoff at 1000 daltons). The degradation of these labeled chlorolignins was studied by measuring evolved **1**4CO//2 using two different bacterial mixtures, isolated from aerated lagoons receiving spent bleach liquors, and the white-rot fungus Sporotrichum pulverulentum. The results obtained showed that the bacterial consortia degraded high molecular mass chlorolignins only very slowly, less than 4% of the **1**4C material being converted to **1**4CO//2 within 3 months. However, the fungus degraded the same material much more rapidly, 35-45% of available **1**4C being converted to **1**4CO//2 within 2 months.