Isolation And Characterization Of Lead-tolerant Fungi

With the rapid development of industry and agriculture,heavy metal pollution on the ecosystem and human health poses a great threat and harm,causing serious environmental problems,the urgent need to develop practical and practical methods to alleviate and repair heavy metal pollution of soil and wastewater Physical and chemical methods to deal with heavy metal pollution is expensive and difficult to operate,and microbial method because of economic,efficient,environmental protection and no secondary pollution,etc.,in dealing with heavy metal pollution has been widely concerned about the experiment by separating domestication from lead contaminated soil The results were as follows:?1?A lead-resistant fungus was screened by dilution coating plate method using lead-contaminated soil near a lead-acid battery factory in Changsha,Hunan Province,and its tolerance to lead was 30 mmol/L.?Paecilomyces lilacinus sp.?,Named LRP01,and LRP01 has some tolerance to heavy metals other than lead.20 mmol/L Cu²⁺,12mmol/L Cd²⁺,10 mmol/L Co²⁺,20 mmol/L Cr²⁺,40 mmol/L Mn²⁺,25 mmol/L Ni²⁺,20 mmol/L Cr⁵⁺.?2?The optimum medium conditions for LRP01 were:potato medium,sucrose20 g/L,NaCl 0 g/L.The optimized culture conditions were as follows:pH 7,mass 6 g g/L,temperature 30?,speed 200 rpm.Through the antimicrobial susceptibility test of20 kinds of antibiotics,it was found that LRP01 was sensitive to penicillin,and the inhibition was only 8 mm.The sensitivity of tetracycline,cefuroxime and doxycycline was the highest,and the inhibition was above 30 mm.?3?The adsorption conditions of LRP01 were optimized as follows:the pretreatment of freezing at 2?f or 80 h,pH 5,temperature 25?,speed 220 rpm,5 g/L,and Pb²⁺at 100 mg/L Rate reached 89.4%.Zn²⁺>Na⁺>Ca²⁺,and the presence of Ni²⁺,Cr⁵⁺,Cu²⁺,Cd²⁺,Co²⁺in the presence of Zn²⁺,Mn²⁺,Na⁺,Ca2+in lead-containing medium can promote the adsorption of lead to LRP01 Inhibition of LRP01 adsorption on lead,the effect of inhibition is Cr⁵⁺>Ni²⁺>Cu²⁺>Co²⁺>Cd²⁺.?4?The growth of tobacco seedlings was studied by LRP01,and the results showed that LRP01 could promote the growth of tobacco.Under the condition of lead-free condition,the plant height and root length of tobacco were increased 27.9%and 6.8%respectively.The fresh weight of aboveground and root increased by 65.3%and 76.8%respectively.The dry weight of ground and root increased by 50%and121%respectively.LRP01 promoted the absorption of lead in tobacco and 400 mg/kg Pb²⁺.Inoculation with LRP01 resulted in the absorption and accumulation of lead in roots,stems and leaves of tobacco According to the increase of 31.3%?28.89%?40.26%,1200 mg/kg Pb²⁺,respectively,it was31.19%?32.4%?34.56%.It is expected that the application of LRP01 to super-accumulated plants will absorb heavy metals in soil and reduce the content of heavy metals in soil.