en Environmental Health, Sciences, and Engineering Environmental Health, Sciences, and Engineering پژوهشي Original Article <p style="text-align: justify;"><span style="font-size:14px;"><span style="font-family: times new roman;"><strong>Background;</strong> Enzymes are well known as sensitive catalysts in the laboratory and industrial scale. To improve their properties and for using their significant potential in various reactions as a useful catalyst the stability of enzymes can often require improvement. Enzymes Immobilization on solid supports such as epoxy- functionalized ferric silica nanocomposite can be effective way to improve their characteristics.<br> <strong>Methods; </strong>In this study silica coated magnetite nanoparticles were Functionalized with GPTSM as a linker, then immobilization reaction performed by using&nbsp; various amounts of lipase B from Candida Antarctica (CALB), for the next step immobilization effects on thermal stability and optimum pH were investigated in comparison with free CALB.</span></span><br> <span style="font-size:14px;"><span style="font-family: times new roman;"><strong>Results; </strong>Results illustrated enzyme was successfully immobilized on nano particles and immobilized derivative retains 100% of its activity by 55&deg;C while free CALB loss its activity at the same condition.</span></span><br> <span style="font-size:14px;"><span style="font-family: times new roman;"><strong>Conclusion; </strong>Immobilization of CALB on Fe₃O₄@SiO₂ particles resulted in significant improvements in its characteristics such as thermal stability and methanol tolerance compared to the free CALB.</span></span></p> Immobilization, Candida antarctica lipase B, Silica nanocomposite magnetite 183 188 http://jhehp.zums.ac.ir/browse.php?a_code=A-10-54-2&slc_lang=en&sid=1 Javad Mohammadi m.javad47@gmail.com 10031947532846009339 10031947532846009339 No Department of Environmental Health Engineering, School of Public Health, Zanjan University of Medical Sciences, Zanjan ,Iran. Mehdi Mohammadi E-mail: M.mohammadi@nigeb.ac.ir 10031947532846009340 10031947532846009340 No National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran. Mohammad Reza Mehrasbi zmehr@zums.ac.ir 10031947532846009341 10031947532846009341 Yes Department of Environmental Health Engineering, School of Public Health, Zanjan University of Medical Sciences, Zanjan ,Iran Mazyar Peyda mazyarpeyda@zums.ac.ir 10031947532846009342 10031947532846009342 No Department of Environmental Health Engineering, School of Public Health, Zanjan University of Medical Sciences, Zanjan ,Iran