Bioweathering Of Hematite By Trichoderma Harzianum

In China,arable land is approximately 1.8 billion acres.Although it ranks the fourth in the word,its percapita availability is very low.Meanwhile,the fertile land is less than 1/3 in China.Owing to the long-term surfeit use of excessive fertilizer,the content of soil organic matter is only about one fourth to two fifths of that of soil organic matter in the United States and Europe.In addition,half of usable land is lack of trace elements and 70%-80%of it has not enought nutrient,too.Therefore,it's very important to improve the content of soil organic matter and trace elements.Here the biomineralization process of hematite by Trichoderma harzianum were studied.Specifically,XRD,TEM and SEM were used to observe mineral morphology and structure changes.Combind SR-FTIR and ?-XRF,the spatial distribution of Fe and characterization of their associations with organic or inorganicfunctionalgroups were in situ observed at the micrometer scale.Main results of this paper are listed as follows.1)The co-culture of hematite and T.harzianum showed that the pH maintained stable until 24 hours,then slowly reduced to 2.34 at the 66th hour.The amount of Fe element was from 0 to 1.25 mg/L.These findings indicated that microbial exudates resulted in the decrease of pH values during incubation experiment.2)The result from XRD and TEM showed that the growth and metabolism of bacteria would destroy morphology and crystal structure of hematite.Meawhile,new active minerals were formed during the incubation experiment.3)Analysis of the SR-FTIR and ?-XFR revealed that organic functional groups were heterogeneously distributed at the surface of minerals.Meanwhile,a significant positive correlation between organic groups and inorganic groups was built.The correlation coefficient was larger than 0.5 and even greater than 0.86 for carboxylic carbon and Fe-O.Mycelial growth generated reactive oxygen species(ROS)in the growing tip and cell differentiation.The produce of ROS related closely with mycelial growth and differentiatio.The production of ROS may be responsible for the dissolution of minerals and further the formation of SRO minerals.In summary,co-culture of hematite and T.harzianum in rocking culture experiment showed that growth and metabolism of bacteria can release of mineral elements and the new active minerals have carbon sequestration action,so biomineral can effectively improve soil fertility.