Enzyme activities on decomposing needle litter of Pinus armandii by five dominant saprophytic fungi

Abstract:

[Objective] The purpose of this research was to analyze the changes of enzyme activities and relationships amony enzymes on decomposing needle litter of Pinus armandii by saprophytic fungi and explore fungal decomposition capacities of the litter. [Methods] Basing on morphological characteristics and sequence alignment analysis of rDNA-ITS region, five dominant strains isolated from Pinus armandii needle litter from Erlang Mount were identified. These five isolates were used as the fungal strains and the needle litter was used as the natural substrate. The fungi abilities to degrade the needle in terms of the loss in total organic matter (TOM) and the enzyme activities of endoglucanase (EG), xylanase (Xyl), lignin peroxidase (LiP), manganese peroxidase (MnP) and acid phosphatase (AP) by fermentation were tested. [Results] The five isolates were identified as Mucor sp., Pestalotiopsis sp., Allantophomopsis sp., Phoma sp. and Hypocrea sp., respectively. The loss in TOM caused by the five fungi was between 6.63%?15.77%. AP activity in the case of Pestalotiopsis sp. was the highest and the activities of EG, Xyl, LiP were relatively high. LiP activity was the highest in Allantophomopsis sp., which had high activity of MnP. Whereas EG and Xyl activities were low for Hypocrea sp. which can secrete LiP and higher AP. The results of correlation analysis showed that AP activity was negatively correlated with the loss in TOM. Moreover, there was a certain synergy between EG, Xyl and AP, especially between EG and AP. [Conclusion] In the present study, the five saprophytic fungi can degrade needle litter of Pinus armandii and the ability from highest to lowest was as followed: Pestalotiopsis sp., Allantophomopsis sp., Hypocrea sp., Phoma sp., Mucor sp.. Enzyme activities and enzymes synergy had an influence on decomposition of the needle litter. Pestalotiopsis sp., Hypocrea sp. and Allantophomopsis sp. were found to not only be capable of producing lignocelluloses-degrading enzymes but cause higher loss in TOM. These three strains were regarded as lignocelluloses-degrading fungi.