Utilization of dimeric lignin model compounds by mixed bacterial cultures

The degradation of dimeric phenylpropanoid lignin model compounds using mixed bacterial cultures was studied. The six model compounds contained the most common linkages of lignin: beta-O-4, beta-beta, beta-5 and beta-1. The results indicate that it is possible to enrich bacteria which are able to degrade all these compounds. Bacteria were also able to use these dimers as the sole source of carbon for growth. In view of these results it seems probable that bacterial inability to degrade polymeric lignin in due to the physical properties such as the molecular size of lignin.Peer reviewe

Quantitative lignin analysis based on permanganate oxidation

Aromatic acids obtained on permanganate oxidation of pretreated (cleavage of ethers and alkylation of phenolic groups) lignins offer a possibility to estimate the amounts of differently substituted aromatic units in lignins. An equation is derived to simplify the calculation of the gross composition of lignins based on the yields of methoxy-substituted aromatic acids obtained on permanganate oxidation of lignins with methylated phenolic groups. The fact that only phenolic groups yield degradation acids makes it possible, under certain conditions, to use the equation for the estimation of the phenol content in a lignin sample