Manganese-enhanced degradation of lignocellulosic waste by Phanerochaete chrysosporium: evidence of enzyme activity and gene transcription.

Lignolytic fungi initiate lignocellulose decay by producing extracellular oxidative enzymes. For better understanding the enzymatic degradation of lignocellulose by white-rot fungi, we investigated the effect of manganese on the organic matter loss, manganese peroxidase (MnP) activity, and manganese peroxidase gene (mnp) transcription levels during solid-state fermentation of rice straw with Phanerochaete chrysosporium. The results showed that the addition of manganese improved MnP activity and made it reach the peak earlier, promoted fungal growth at the early period (0-9 days), and enhanced the degradation of lignocellulosic waste. The total organic matter loss had a good correlation with fungal biomass during 30 days of cultivation, and manganese amendment promoted the ability of P. chrysosporium to degrade lignocellulose. Quantitative real-time RT-PCR revealed the differential expression of mnp1, mnp2, and mnp3: manganese amendment increased the transcription of mnp1 and mnp2 but not mnp3. The results indicated that manganese stimulated mnp transcription levels and played a post-transcriptional role in MnP production. These findings provide opportunity of development in enzymatic degradation of lignocellulosic waste by P. chrysosporium amended with manganese.