Hydrotropic lignin has been considerably degraded, therefore, it was easily affected by
Ps. ovalis as the case of lignin preparation from waste liquor of oxygen·alkali pulping (oxygen·alkali lignin)
A great portion of high molecular weight of hydrotropic lignin was appreciably decomposed. Carbonyl group increased remarkably. Nitrogen content of biodegraded lignin increased with progress of bacterial incubation, such as the case of oxygen·alkali lignin.
Polarographic catalytic hydrogen waves of biodegraded hydrotropic lignin were shown to arise from carbonyl group but not protein or amino acids in the degraded lignin.
Vanillin and syringaldehyde yielding groups of hydrotropic lignin decreased by bacterial incubation, however, 5-position condensed guaiacyl type structure increased.
Methoxyl group decreased and phenolic hydroxyl group increased with progress of biodegradation. However, it was suggested that demethoxylation was caused by
Ps. ovalis as other lignin preparations studied in this series, because p-hydroxyl groups and 4-methoxy isophthalic acid type structures of hydrotropic lignin increased by incubation.
A portion of biodegraded lignin was adsorbed to bacterial cells. There was a tendency for the more lignin is biodegraded, the more lignin is adsorbed to bacterial cells.
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