Water-Soluble Pyrolysis Products as Novel Urease Inhibitors Safe for Plants and Soil Fauna

Water-soluble pyrolysis products from lignocellulosic biomassare nonphytotoxic urease inhibitors useful for agricultural applications.Water-soluble compounds (WS) obtained from the pyrolysisof threelignocellulosic biomasses (larch, poplar, and switchgrass) were testedas potential inhibitors of the enzyme urease. Thanks to the presenceof an array of phenolic compounds like catechol, methoxy/hydroxy phenols,phenolic acids, and phenolic aldehydes, all the WS samples testedat a catechol concentration of 30 mu M inhibited the activityof jack bean urease (JBU) by 60%-70% and by 80% that of ureasenaturally present in the soil. A 10 times lower dose of WS samples(catechol concentration of 3 mu M) inhibited the activity of JBUby 20%, while that of soil urease by 50%, in line with the known inhibitionof N-(n-butyl) thiophosphoric triamide(NBPT). The germination rate, early growth, and development of oatwere not affected by any WS sample tested at this lower dose, as wellas the cress germination rate, while the development of cress rootsand shoots was lower than the control presumably because of the lowpH of the tested WS solutions. Earthworm survival was not significantlyaffected by any WS sample tested, but an effect was observed on theability of the eggs to develop into viable newborns.