Anais do Congresso Paranaense de Microbiologia
Anais do III Congresso Paranaense de Microbiologia

The search for modernization of industrial processes is essential to market competitiveness and to change the current model of unsustainable production, which is highly dependent on non-renewable resources. Lignin, for example, is a very abundant natural and renewable polymer on Earth, which may form a number of important compounds for the industry, but its use as a raw material is still poorly exploited. In order to promote new researches on the production of commercially important compounds by biological means, the objective of this study was to analyze the profiles of metabolites resulting from the biotransformation of the Kraft lignin, from the enzymatic action of two selected fungal isolates: Br-274 and JUMAD002. A total of ninety three fungal isolates were obtained from mushrooms growing in forest fragments, coffee grounds, as well as other previously isolated organisms, composing the QuiMiBio fungal collection of UTFPR Londrina. Nine pre-selected microorganisms were evaluated by the mycelial growth in solid medium containing Kraft lignin as sole carbon source. Subsequently, two fungi were selected for the experiment of biotransformation of Kraft lignin in Vogel liquid medium during 7, 14 and 21 days. For each culture time, a cell free extract (CFE) was obtained to quantify laccase activity by ABTS oxidation. Furthermore, the CFE was extracted with ethyl acetate and submitted to HPLC with gradient elution using water and acetonitrile with 1% trifluoracetic acid. The results in solid medium showed good mycelial growth of the fungi JUMAD002 and Br-274 and medium color change for the first one, so these two microorganisms were selected for the biotransformation experiment. The maximum laccase activity was 9,0 U/ml in 21 days and 4,0 U/mL in 14 days for Br-274 and JUMAD002, respectively. Analysis of the metabolite profiles revealed that Br-274 did not form new compounds. The chromatogram resulted from the 21 days incubation of the fungal isolate JUMAD002 with Kraft Lignin revealed three possible metabolites (T9, T10 and T11) from the enzymatic transformation of the polymer, encouraging the continuation of the study. Finally, our research confirmed the potential of fungi to promote chemical changes in Kraft Lignin by extracellular enzymes and stated a possible alternative for refining industry.