The Influence Of A Lithophyte Actinomycete On The Morphology Of Carbonate And Its Holding Effect On Metal Cations

Lithophilous actinomycetes are one of the main microbial groups in karstic region.They have an important influence on biomineralization and morphology change of carbonate which is still relatively weak field.The researches on biomineralization mediated by lithophilous actinomycetes do not only conductive to understanding geological process and mechanism of actinomycetes on the surface of rocks,but also fixed heavy metal ions.So,it has important research value.The strain DHS C013T which was isolated from the surfaces of rocks in the karstic region was used to induce the formation of calcium carbonate and promote the immobilization of Fe3+ and Cu2+,using ammonium carbonate free dissipation method.Collected the supernate and hypha pellets in the malt extract-glucose-yeast extractpeptone(MGYP)liquid medium by centrifugation and then putted them and fermentation broth,sterile MGYP liquid medium and ultrapure water into metallogenic solution respectively composited by NaHCO3 and Ca(NO3)2·4H2O.Let stand for eight days,scanning electron microscope was applied to observe the sediment at the bottom of the petri plate.In metallogenic system with ultrapure water,only standard calcite of six square was found,however,the special form of CaCO3,such as dumbbell-like,spherulite and the scaly cylindrical shapes were found in metallogenic system with actinomycetes,hyphae fragment and their cell metabolism products.In addition,we put Fe3+ and Cu2+ into the same metallogenic fluid.The results show that polygon carbonate containing Cu2+ and spherical carbonate containing Fe3+ was found in metallogenic system with fermentation broth.It provides new information for fixed heavy metal ions by the method of biological mineralization.The strain DHS C013T was inoculated into the beef extract peptone medium liquid with Ca2+ or yeast extract-malt extract liquid medium with Cd2+.The culture of the pH,carbonic anhyarase activity and Ca2+ concentration was detected in the supernatant at different time,at the same time,the morphology of carbonate was observed by the scanning electron microscope and composition of particles containing cadmium was analysed by XRD.The results showed that the strain can significantly reduce the concentration of Ca2+ and Cd2+ in the liquid culture medium,respectively,from 3.65072ppm down to 1.5361 ppm or so,0.6882ppm decreased to about 0.1682ppm;pH value increased to 8 and above.It was found that CaCO3 particles formed in the beef extract peptone medium liquid with Ca2+,while CdO particles formed in the ISP2 liquid medium with Cd2+.The results provide new evidences for better understanding biominerilization by actinomycetes and their metabolic,and provide a new train of thought for use karstic actinomycetes to restore soil and water heavy metal.