YUMEI SUN, ZHANGUO NING, FAN YANG and XIANZHEN LI* School of Biological Engineering, Dalian Polytechnic University, Dalian, PR China *Corresponding author: Xianzhen Li, School of Biological Engineering, Dalian Polytechnic University, Dalian, PR China; e-mail: xianzhen@mail.com Submitted 13 October 2014, revised 18 February 2015, accepted 18 February 2015 https://doi.org/10.5...