Presently, most of the alginate produced commercially is still obtained from algae, although it is subjected to variations in quality and quantity due to changes of climate and sources. Alginate can also be biotechnologically produced by species of two families of heterotrophic bacteria, Pseudomonas and Azotobacter. Efforts have been made in the past to produce alginate-like polymers from these bacteria. The association of virulence with alginate production in most Pseudomonas spp. has made Azotobacter vinelandii the most promising candidate for the industrial production of alginate. Nevertheless, for specific and well-defined applications, especially in biomedical and pharmaceutical fields, the production of Pseudomonas alginate has attracted increasing attention. Microbial alginate production has been widely investigated in batch, fed-batch, and continuous cultures. This chapter summarizes current knowledge of physiology and process aspects in view of potential industrial production of microbial alginate.