Maltose syrups have got wide-range utilizations in a variety of applications from bakery to drug-development. α-Amylases are among the most widely utilized industrial enzymes due to their high specificity in production of maltose syrup from starch. However, enzymes are not stable in ex vivo conditions towards alteration in pH, temperature, and such other parameters as high salt concentrations and impurities, where immobilization is required to advance the stability of the enzyme with which approach the requirement of isolation of the enzyme from media is eliminated as well. In this study, Termamyl α-amylase was immobilized on the none-modified chitosan beads (NMCB), L-lysine-modified chitosan beads (LMCB), and L-asparagine-modified chitosan beads (AMCB) to assess effects of the support material on optimum conditions and kinetic parameters of the α-amylase activity in production of maltose from starch. Immobilization on NMCB, LMCB, and AMCB puts a strong influence on optimum pH, optimum temperature, stability, and kinetic parameters of α-amylase. Modification of chitosan beads with L-lysine and L-asparagine dramatically altered the overall immobilization yield, and enzyme's response to pH and temperature variations and the kinetic parameters. AMCB provided the best immobilization yield (49%), while LMCB only improved the yield by 2% from 22 to 24%.

In this study, the effects of different nitrogen sources on lentil (Lens clunaris) and barley (Hordeum vulgare) plants, exposed to 5 and 10 mM boron stress previously, were studied. After ten-day germination, the lentil (native) and barley (Tokak157/37) were incubated 16 h light and 8 h dark per day for 7-day growth cycle under the conditions of boron stress via different nitrogen sources (10 mM nitrogen in NH 4 Cl, KNO 3 and urea). As a result of the changes in the nitrogen sources of the plants, there were determined decreases in the relative growth rate (%) and total chlorophyll content related to boron stress, (p < 0.05) and (p < 0.01), respectively. The changes in the lentil were obtained much more than those in the barley. In addition, the changes in the groups in which NH 4 + was used as nitrogen source were obtained at lowest levels. The concentrations of MDA, H 2 O 2 and proline showed increases under boron stress (p < 0.05). The effect of boron toxicity on the activities of SOD, GPX and LOX was similar in the two species but the levels of CAT and APX activities were different in both species under 5 and 10 mM boron stress (p < 0.01). SOD, GPX and LOX activities increased in the roots and shoots of boron treated plants as compared with the controls (p < 0.01). Although, lentil CAT and APX, activities decreased; in barley, CAT and APX, activities increased under boron toxicity. In conclusion, the fertilizers which contain NH 4 + should be used in the boron stressed farmlands.