Background: Omega-3 polyunsaturated fatty acids (n-3 PUFA) have been used in the treatment of inflammatory bowel diseases (IBD) and irritable bowel syndrome (IBS), and their effects are potentiated upon conversion to specialized pro-resolving mediators (SPM). Recent studies indicated that the probiotic bacterial strain Bacillus megaterium DSM 32963 can be used to enhance the production of SPM and its precursors in vivo. Methods: Here, we explored the contribution of Bacillus megaterium DSM 32963 to SPM production in a validated, dynamic model of the upper and lower intestine. The TIM-1 and TIM-2 models were applied, with the TIM-2 model inoculated with the fecal microbiota of healthy individuals and probed with an n-3 PUFA lysine salt with and without Bacillus megaterium DSM 32963 or an SPM-enriched fish oil or placebo. Kinetics of SPM production were assessed by metabololipidomics analysis, and survival and engraftment of the Bacillus megaterium strain was monitored by plate counting and by strain-specific qPCR. Results: Bacillus megaterium DSM 32963 poorly survived TIM-1 conditions but propagated in the TIM-2 model, where it enabled the metabolism of n-3 PUFA to SPM (resolvin E2 and protectin DX) and SPM precursors (e.g., 5-hydroxyeicosapentaenoic acid (5-HEPE), 15-HEPE, 18-HEPE, 4-hydroxydocosahexaenoic acid (4-HDHA), 10-HDHA, and 17-HDHA, among other EPA- and DHA-derived metabolites) with significantly higher levels of lipid mediator production compared to the n-3 PUFA lysine salt alone; esterified n-3 PUFA were hardly converted by the microbiota. Conclusions: These findings reinforce that Bacillus megaterium DSM 32963 facilitates SPM production in situ from bioavailable n-3 PUFA in the large intestine, highlighting its use to complement eukaryotic SPM biosynthesis by the host and its possible therapeutic use for, e.g., IBD and IBS.

The gut–brain axis plays a pivotal role in mental health, with synbiotic supplements emerging as promising interventions for stress and anxiety management. This observational open-label pilot study aims to evaluate the effects of a symbiotic supplement containing Bacillus subtilis DSM 32315 and L-alanyl-L-glutamine, delivered via a targeted colonic-release capsule, on stress, anxiety, and mental wellbeing. Conducted as a non-placebo-controlled real-world case study, the study recruited 100 adults with elevated perceived stress and followed them for over eight weeks. Validated self-reporting tools, including the Depression Anxiety Stress Scales-21 items (DASS-21), Perceived Stress Scale-10 items (PSS-10), Athens Insomnia Scale (AIS), Short Form Health Survey-12 items, and Gastrointestinal Symptom Rating Scale questionnaires, were used to assess outcomes. Statistical analyses, primarily using linear mixed models, indicated reductions in DASS-21, PSS-10, and AIS scores, along with self-reported improvements in gastrointestinal symptoms and mental well-being. These findings should be interpreted cautiously due to the exploratory, uncontrolled study design. Notably, DASS-21 total scores declined within one week, with reported benefits sustained at four and eight weeks. However, these rapid changes may partly reflect expectancy effects or regression to the mean. These observations provide valuable insights for further hypothesis generation, notably that the synbiotic supplement could support stress management and mental health by modulating the gut–brain axis. However, further placebo-controlled trials including measurement of relevant biomarkers are warranted to confirm these observations and explore underlying mechanisms.