The cyanobacterial extracellular polymeric substances (EPS) are heteropolysaccharides that possess characteristics suitable for food and pharmaceutical applications. In this work, an extracellular carbohydrate polymer isolated from the marine cyanobacterium Cyanothece sp. CCY 0110, alone or combined with arabic gum, was tested for the microencapsulation of the vitamin B12, the most chemically complex and the largest molecule among all the vitamins. The incorporation of vitamins into food systems can provide a simple way to develop new functional foods. The microencapsulation by a spray-drying process and the controlled release of vitamin B12 were studied. Arabic gum and cyanobacterial polymer or only cyanobacterial polymer were used as encapsulating agents. The microparticles obtained were evaluated and characterized in terms of morphology, size and release profiles. Spherical microparticles with a very rough surface were obtained. The microparticles prepared only with cyanobacterial polymer presented a mean diameter of approximately 8 mu m, while the ones prepared with cyanobacterial polymer and arabic gum presented a smaller size. The main kinetic release models (zero and first order kinetics and the Higuchi, Korsmeyer-Peppas and Weibull models) were adjusted to the experimental release profiles. The model that best describes the release profile for the microparticles prepared with cyanobacterial polymer is the kinetics of first order, while for the ones prepared with cyanobacterial polymer and arabic gum, the Weibull model presents the best fit to the experimental values. (C) 2018 Elsevier B.V. All rights reserved.