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A novel method has been developed to easily hydrolyze cellulose to sodium cellobionate in a filamentous fungas, Neurospora crassa. The objectives of this experiment were to investigate the in vitro biological activities of sodium cellobionate. Antioxidant activity was evaluated with 3 chemical-based assays, including DPPH radical scavenging assay (DPPH), Trolox equivalent antioxidant capacity assay (TEAC), and ferric reducing antioxidant power assay (FRAP). Antimicrobial activity was determined as minimum inhibitory concentration (MIC) that prevented growth of tested bacteria, including four gram-negative bacteria (Escherichia coli F18 and ATCC 25922, and Salmonella Typhimurium ATCC 14028 and a wild strain isolated from cull diary cows in California) and one gram-positive bacteria (Enterococcus faecalis ATCC 29212). Anti-inflammatory activity was tested by analyzing TNF-α production with porcine alveolar macrophages that were challenged with lipopolysaccharide. A porcine intestinal epithelial cell line, IPEC-J2, was also used to test the effects of cellobionate on cell proliferation of intestinal epithelial cells. The tested doses of sodium cellobionate were 0, 0.04, 0.20, 1.00, 2.00, 4.00, 20.00, and 40.00 mg/mL. All assays were performed with over 6 replicates, except that MIC assays were performed as triplicate. All data were analyzed by PROC MIXED of SAS. Sodium cellobionate did not have radical scavenging capacity, but had weak FRAP (9.68 µM L-Cysteine equivalent) and TEAC (69% reduction) at the dose of 40 mg/mL. MIC results revealed that sodium cellobionate did not inhibit the growth of all tested bacteria, indicating it does not have antimicrobial activity within the range of tested doses. Sodium cellobionate did not exhibit anti-inflammatory activities, but significantly enhanced (P < 0.05) intestinal epithelial cell proliferation in vitro by 24.00%, 39.64%, and 25.98% when the doses were 1.00, 2.00, and 4.00 mg/mL, respectively. Results of this experiment indicate that cellobionate has limited biological activities in vitro, except that this biomass product could strongly stimulate the proliferation of intestinal epithelial cells. Future research will focus on the potential impacts of sodium cellobionate on intestinal physiology in vivo. [ABSTRACT FROM AUTHOR]