Assessment strategy for bacterial lignin depolymerization: Kraft lignin and synthetic lignin bioconversion with Pseudomonas putida

In order to better understand bacterial depolymerization of lignin, a new analytical approach was proposed using Pseudomonas putida KT2440 as delignifying bacterium and Escherichia coli non-delignifying control. Two different types lignins, technical Kraft lignin synthetic dehydrogenopolymer (DHP), were submitted bioconversion kinetic study over 7 days. The concomitant analysis the supernatant acid-precipitable fraction water-soluble extractives by high-performance size-exclusion chromatography (HPSEC) gas – mass spectrometry (GC–MS) highlighted specific action P. towards these substrates, with transitory formation phenolic metabolites (dihydroferulic acid for lignins dimers DHP) prevention self-assemblying. both cases apparent followed repolymerization observed. pellets indicated time-increasing content associated cells, which could account structural changes observed E. in supernatant. • Incubation prevented self-polymerization lignin. Apparent DHP took place during incubation KT2440. metabolized monomers first 24 h incubation. Dihydroferulic formed treatment KT244. Lignin found after