Hericium erinaceum is an edible mushroom, known as Lion's mane mushroom (Yamabushitake in Japanese). We prepared the crude enzyme from H. erinaceum and evaluated the rheological properties on the milk coagulation process and analyzed texture of the resultant curd with the enzyme. The crude enzyme from H. erinaceum could clot not only the low heat (LH) milk treated at 66℃ for 30 min but also the ultra-high temperature (UHT) milk at 130℃ for 2 sec. The temperature dependences of dynamic viscoelastic moduli indicated that the storage modulus and the loss modulus of the resultant curd of LH-milk with the crude enzyme from H. erinaceum was relatively lower than with chymosin. Moreover, RP-HPLC analyses revealed that the milk-clotting process by the action of the crude enzyme from H. erinaceum might not be dependent on the cleavage of κ-casein. Our data suggested that the crude enzyme from H. erinaceum might be utilized for the production of a new type of cheeses.

　Many species/strains of Lactobacillus colonize in the gastrointestinal tracts of animals including human, and some of them are used as probiotics. Lactobacillus reuteri is frequently isolated from the gut of wide range of animals, and thus as a model of the intestinal microbiota, investigations on mechanism of their colonization are underway. While previous studies have described some L. reuteri adhesins, comparative analysis of those proteins have rarely been pursued. In the current study, L. reuteri DSM 20016^T was recruited and its potential adhesion factors were evaluated. After L. reuteri DSM 20016^T was exposed in simulated gastrointestinal conditions, the remaining adhesins were detected. As a result, the adhesins were relatively resistant to simulated gastric juice but were sensitive to simulated intestinal fluid. RT-qPCR was used to examine changes in the expression of the proteins, and results indicated that the expression of the adhesins tended to be promoted in comparison with their expression during normal culturing. In conclusion, the in vitro assay of this study suggested that cell-surface adhesins of L. reuteri could be damaged by digestive process but the bacterium may be capable of reproducing those proteins thereafter.

　Recently, improper use of antibiotics in human and animals is to a large degree involved in the emergence of multi-drug resistance bacteria. Lactic acid bacteria (LAB) are known as useful microorganisms, and the bacteriocins produced by LAB kill closely related bacteria. In this study, we examined whether bacteriocins can suppress drug resistance bacteria, and the selected bacteriocins were characterized.

　The 27 strains were selected from the 908 of LAB strains by antibacterial assay against Lactobacillus delbrueckii subsp. bulgaricus JCM1002^T and Bacillus sp. C107. Total 11 strains of drug resistance bacteria were isolated from foods and porcine feces. The culture supernatants from the selected LAB showed antibacterial activities against drug resistance bacteria. The antibacterial activities of the culture supernatants from the selected LAB were tested against JCM1002^T after pH adjustment at 6.2, protease treatment at 37℃ for 18 h, and heat treatment at 121℃ for 15 min, and a heat-map dendrogram was constructed. Their antimicrobial activities were grouped according to their pH-dependency and heat-resistance. Especially, the culture supernatant of Lactococcus lactis MBR916 showed high protease stability. The antimicrobial spectrum suggests that MBR916 produces a nisin-like bacteriocin. The molecular weight of MBR916 bacteriocin, however, was estimated to be about 4200 by SDS-PAGE and in situ antibacterial assay that was different from that of nisin A. Moreover, protease stability of bacteriocin was higher than nisin A. These suggest that the bacteriocin of MBR916 may be novel.