Effects of the polysaccharides alginate and locust bean gum, and oligosaccharides oligomannuronate (OM) and oligoguluronate (OG) on glucose oxidase (GOD) production by Penicillium variabile P16 were studied. Small increases were observed when the cultures were supplemented with OG and OM blocks with an average degree of polymerization (DP) of approximately ten. With 200 mg l(-1) OM blocks addition at 0 h, the increase reached 32.1% compared with the control; however regardless of the time of addition, large increases (np to approximately 70%) in GOD production were obtained with 100 and, particularly, 200 mg l(-1) of alginate-derived oligosaccharides (OG and/or OM blocks) with a DP of approximately seven. No significant influence was observed on mycelial biomass.