Acknowledgements
We would like to thank CNPq and PADC-FCFAr for financial support. We gratefully recognize the support from the Spanish Government, grant CTQ2009-07568. The help and comments from Dr.Ángel Berenguer (Instituto de Materiales, Universidad de Alicante)are kindly acknowledged.
It has been established a simplified procedure for the preparation of immobilized beta-amylase using non-purified extract from fresh sweet potato tubers. Although the procedure was very straight forward, an enzymatic derivative preparation with good catalytic properties was obtained. Beta-amylase from sweet potato is a promising element for study, in both its free or immobilized form because of its easy-to-find and cheap source, and its stability and immobilization possibility. Beta-amylase glutaraldehyde derivative has shown to be very interesting and offer advantages over their free form, very likely to the multi point immobilization of the enzyme. It is possible to produce very stable derivatives, with both improved temperature and pH stability. The only drawback of the immobilization is the decrease in enzyme activity, that seems to be mainly due to diffusion limitations of the starch inside the pores of the enzyme, that could be modulated by using supports with higher pore diameter (e.g., agarose 4%) or by the use of lower particle size (this point may promote some difficulty to the industrial management of the biocatalyst) [22].