Effect of Geobacillus toebii GT-02 addition on composition transformations and microbial community during thermophilic fermentation of bean dregs

Bean dregs can be prepared into organic fertilizer by microbial fermentation. Geobacillus toebii GT-02, which has promoting effect on bean dregs fermentation, was isolated from horse dung and it grows within a range of 40–75 °C and pH 6.50–9.50. The effectiveness of GT-02 addition on composition transformations and the microbial community in bean dregs thermophilic fermentation at 70 °C for 5 days was investigated (T1). Fermentation of bean dregs without GT-02 served as control (CK). The results showed that T1 (the germination index (GI) = 95.06%) and CK (GI = 86.42%) reached maturity (defined by GI ≥ 85%) on day 3 and day 5, respectively. In addition, the total nitrogen loss of T1 (18.46%) on day 3 was lower than that in CK (24.12%). After thermophilic fermentation, the total organic carbon and dry matter loss of T1 (53.51% and 54.16%) was higher than that in CK (41.72% and 42.82%). The mean microbial number in T1 was 4.94 × 107 CFUs/g dry matter, which was 5.37 times higher than that in CK. 16S rDNA sequencing identified Bacillus, Geobacillus and Thermobacillus as dominant in CK, while Bacillus, Ammoniibacillus and Geobacillus were dominant in T1. A canonical correspondence analysis showed that Geobacillus and Ammoniibacillus were positively correlated with the GI. Thus, thermophilic fermentation with GT-02 can promote the maturity of bean dregs, which indicated the potential application value of GT-02 in thermophilic fermentation.

Optimization of Fermentation Process for Improving Soy Isoflavones Aglycone Content in Bean Dregs by Lactobacillus plantarum PL70a

Aglycone-type soy isoflavones have higher biological activity than glycoside-type soy isoflavones. Bean dregs are rich in glycoside-type soy isoflavones. In order to improve the biological activity of soy isoflavones in bean dregs, the Lactobacillus plantarum PL70a was screened and the fermentation process of converting glycoside-type soy isoflavones into aglycone-type in bean dregs was optimized by single-factor experiments and the response surface methodology. The optimal fermentation process was as follows: (NH4)2SO4 was added in an amount of 0.17%, glucoamylase was added in an amount of 0.87%, inoculation amount was 17%, sucrose was added in an amount of 1.3%, and fermentation time was 3 days. Under this process, the content of aglycone-type soy isoflavones in bean dregs significantly increased. Trypsin inhibitors and antigen proteins were almost removed. The fermentation process provides a good reference for the low-cost processing of high-quality soy isoflavone aglycone food.

Effect of Geobacillus toebii addition on composition transformations and microbial community in thermophilic bean dreg composting

A thermophilic bacterium, Geobacillus toebii GT-02, was successfully isolated from horse dung. The effectiveness of Geobacillus toebii GT-02 addition on composition transformations and the microbial community in bean dreg composting at 70°C for 5 days was investigated (T1), and the control consisted of bean dreg compost without GT-02 (CK). After 5 days, T1 presented higher total nitrogen contents (2.77%) and lower carbon-to-nitrogen ratios (14.4) than CK (2.34% and 16.9, respectively). The germination index (GI) of T1 was 135%, which was 56% higher than that of CK (86%). The dry matter loss in T1 was 54.16% (26.82% higher than the CK value (42.82%)). The mean microbial number in T1 was 4.94x107 CFUs/g dry matter, which was 5.37 times that in CK. 16S rDNA sequencing identified Bacillus, Geobacillus and Thermobacillus as dominant in CK, while Bacillus, Ammoniibacillus and Geobacillus were dominant in T1. A canonical correspondence analysis showed that Geobacillus and Ammoniibacillus were positively correlated with the GI. Thus, composting with GT-02 can promote the maturity of bean dregs, and GT-02 has potential commercial application in thermophilic composting.

A Case of Mucor Irregularis-Associated Cutaneous Mucormycosis in the Forearm

A 61-year-old man developed rupture of the left forearm after cupping 1 year ago, which was partially improved after surgical dressing change. However, the lesion site recurred repeatedly since then and no cure was found. In the recent one month, he came to the hospital for treatment due to the increased area of skin rupture. The lesions involved subcutaneous tissue, reaching deep to the fascia layer, with large black mildew spots on the surface and necrosis like bean dregs in the deep part. The lesion was irregular in distribution, with different sizes and unclear boundaries. Blood blisters and papules could be seen on the skin at the edge, with partial rupture and hemorrhage.