Biodethatching Using Fungal Laccases.

One major problem in management of turfgrass greens is the formation of thatch and mat layers. High organic matter accumulation in the form of thatch or mat causes problems such as decreased movement of oxygen through the thatch or mat zone, decreased saturated hydraulic conductivity, and increased water retention in the thatch zone. These primary problems may further lead to some secondary problems such as wet wilt, soft surface, black layer, limited rooting and extra-and intra-cellular freeze damage. Cultural practices like core aeration, vertical mowing, and top dressing have been used to manage the thatch buildup but are not sufficiently effective. On the other hand, these cultural practices are intensive in terms of cost, energy, and labor as well as have adverse effects on turfgrass quality. It is believed that the rate of thatch degradation is limited by lignin, a plant cell wall constituent that is resistant to microbial degradation. Lignin limits the availability of easily degradable cellulose and hemi-cellulose to the microbes. Natural degradation of lignin is carried out in the environment by certain white-rot fungi which solubilize and mineralize lignin with the help of lignolytic enzymes and hence exposes cellulosic materials for further bacterial degradation in the environment. In this study, we developed a novel approach of thatch management in which we use fungal laccase, a lignolytic enzyme, to facilitate lignin degradation and in turn expose cellulose and hemicellulose for microbial degradation. After nine months of enzymatic treatments at different activity levels in a greenhouse pot study on bentgrass, we observed a significant increase in saturated hydraulic conductivity and a significant decrease in total organic content and thatch layer thickness.