A Study to Investigate Efficacy and Safety of KBL697 in Patients With Mild to Moderate Active Ulcerative Colitis

Inclusion Criteria: * Patient has an established diagnosis of ulcerative colitis for at least 3 months prior to Screening * Patient has active mild to moderate ulcerative colitis at Visit 2 * Patient is taking at least one of the following oral medication: 5-ASA, Corticosteroids, Immunomodulators Exclusion Criteria: * Patient has a possible or confirmed diagnosis of Crohn's Disease or other forms of inflammatory bowel disorders * Patient has a persistent fever of ≥ 38.3°C * Patient has current signs or symptoms of infection * Patient has any immunosuppressant condition * Patient has a known malignancy within 5 years prior to Screening * Patient who has a medical history of drug abuse or alcohol abuse * Patient who, in the opinion of the Investigator, has a clinically significant co-morbid disease * Patient has hepatic failure * Patient is pregnant or plans a pregnancy within the study period * Patient has no previous history of treatment for ulcerative colitis (treatment-naïve patient) * Patient has ongoing or failed treatment for ulcerative colitis with calcineurin inhibitor * Patient has received biologic medication * Patient has received antibiotics within 4 weeks prior to Visit 2 * Patient is unable to stop previous antibiotics treatment during study period * Patient has received probiotics within 2 weeks prior to Visit 2 * Patient with history of major surgery in any region of the gastrointestinal tract * Patient has received any investigational product or participated in another clinical trial * Patient has a stool culture or other examination positive for an enteric pathogen * Patient tests positive for CMV by PCR test at Screening * Patient tests positive for HIV at Screening * Exclusion criteria based on results of Hepatitis B at Screening * Exclusion criteria based on results of Hepatitis C at Screening