Production of dextran by immobilized Lactobacillus acidophilus ST76480.01was intensively investigated. Adsorption was the most suitable immobilization technique for production of dextran and Luffa pulp was the preferred matrix recording (4.74 U/mg protein) of dextransucrase activity and (5.28 mg/ml) of dextran yield. During semi continuous cultivation, adsorbed cells on Luffa pulp retained about 84% of dextransucrase activity and 26% of dextran yield respectively at the 8^th run. The fraction obtained at 65% ammonium sulphate saturation was the richest in its protein content contributing about 4.05% of the total recovered protein, and the highest recovery of dextransucrase activity, about 3.34 % of the culture supernatant. By immobilizing of dextransucrase on chitosan, the highest dextransucrase activity (5.06 U/mg protein) was obtained, achieving 4.4 fold increase than that of entrapping one in alginate, and 2.8 fold of the free enzyme. The enzyme showed a high thermal stability and retained about 60% and 33% of its original activity when heated for 30 min and 60 min respectively at 80^oC. MnCl_2, CaCl₂ and KCl enhanced the activity for both free and immobilized enzymes, while ions, as HgCl_2, BaCl_2, CuSO₄ and EDTA, showed different degrees of inhibition of the tested dextransucrase activity.