The black yeast Aureobasidium pullulans produces abundant soluble β-1,3-1,6-glucan—a functional food ingredient with known health benefits. For use as a food material, soluble β-1,3-1,6-glucan is produced via fermentation using sucrose as the carbon source. Various functionalities of β-1,3-1,6-glucan have been reported, including its immunomodulatory effect, particularly in the intestine. It also exhibits antitumor and antimetastatic effects, alleviates influenza and food allergies, and relieves stress. Moreover, it reduces the risk of lifestyle-related diseases by protecting the intestinal mucosa, reducing fat, lowering postprandial blood glucose, promoting bone health, and healing gastric ulcers. Furthermore, it induces heat shock protein 70. Clinical studies have reported the antiallergic and triglyceride-reducing effects of β-1,3-1,6-glucan, which are indicators of improvement in lifestyle-related diseases. The primary and higher-order structures of β-1,3-1,6-glucan have been elucidated. Specifically, it comprises a single highly-branched glucose residue with the β-1,6 bond (70% or more) on a backbone of glucose with 1,3-β bonds. β-Glucan shows a triple helical structure, and studies on its use as a drug delivery system have been actively conducted. β-Glucan in combination with anti-inflammatory substances or fullerenes can be used to target macrophages. Based on its health functionality, β-1,3-1,6-glucan is an interesting material as both food and medicine.

Heat-killed Fructobacillus fructosus OS-1010 reportedly enhance the number and membrane potential of mitochondria in muscle cell C2C12 in vitro. However, there are no reports on the effects of this strain on mitochondria or the resulting effects on the body in animal models. In this study, we investigated the effects of heat-killed F. fructosus OS-1010 on obesity and other metabolic abnormalities and muscle weakness in mice with high-fat diet (HFD)-induced sarcopenic obesity. C57BL/6 mice were fed HFD supplemented with heat-killed F. fructosus OS-1010 for 13 weeks. The HFD-induced body weight gain was significantly reduced. Additionally, there was a significant decrease in alanine aminotransferase levels, improvement in serum lipid profiles, and a reduction in non-alcoholic fatty liver disease (NAFLD) progression. Skeletal muscle weakness was also mitigated, with changes in gene expression in the quadriceps indicating suppression of intramuscular fat accumulation, and enhancement of mitochondrial density. The findings of this study suggest that heat-killed F. fructosus OS-1010 functions as an anti-obesity postbiotic, potentially benefiting both NAFLD and muscle weakness associated with obesity.

Fructobacillus spp. comprise a large genus of fructophilic lactic acid bacteria whose growth characteristics differ from those of other common lactic acid bacteria. The genus has been extensively investigated microbiologically and phylogenetically. However, knowledge regarding Fructobacillus nutritional benefits remains unclear. In particular, Fructobacillus fructosus OS-1010 (OS-1010) was recently shown to act on intestinal cells to release extracellular vesicle exosomes that act on distant target cells. The released exosomes reportedly enhanced the expression of longevity-associated genes and intracellular mitochondrial activity in muscle cells. OS-1010 is expected to be a functional ingredient that improves the function of distant tissues such as muscles and skin upon oral intake. This study examined the effects of the oral intake of heat-killed OS-1010 on human skin in a randomized, double-blind, placebo-controlled, parallel-group study of healthy participants. Significant improvement in skin elasticity was observed after eight weeks of oral OS-1010 intake. Furthermore, although no significant difference was found between the two groups in a wrinkle-related parameter, the OS-1010 group demonstrated improvements in the percentage wrinkle area and overall average wrinkle depth of crow's feet, which were not observed in the placebo group. These results indicate that OS-1010 can contribute to the improvement in skin conditions.