Isaria cicadae, a medicinal food fungus, is a fruit from Paecilomyces cicadae. In this study, we purified ergosterol peroxide (EP) from the fermentation broth of P. cicadae and investigated its effects on renal cell carcinoma (RCC) cells, in vitro. EP was purified from P. cicadae fermentation broth. The human RCC cell line 786-0 was used to analyze the anticancer mechanism of EP and inhibit its effect on cancer cell proliferation, in vitro. EP with a validated structure showed a yield rate of 20.1 mg/L and a purity of 96%. EP significantly inhibited RCC cell growth and clone formation in vitro. In addition, EP suppressed the migration and invasion, triggered the apoptosis, and modulated the cell cycle of RCC cells, in a dose-dependent manner. It also downregulated β-catenin expression. EP could be routinely produced through P. cicadae. It fights RCC cells in vitro through multiple mechanisms, including suppressing cell growth, colonization, migration, and invasion, arresting the cell cycle, attenuating β-catenin pathways, and triggering apoptosis.

Polysaccharides are an important class of bioactive components of medical mushroom and herbs and are now used as natural drugs or dietary supplements on a global scale. In this paper, we aimed to increase the polysaccharide production of Cordyceps militaris and the antioxidant activities of fermented rice by solid-state fermentation. The media components and culture condition were optimized by orthogonal design and mono-factor tests using rice as the raw material. The optimal media consisted of (g/L): rice (50), fructose (7), glycerin (7), peptone (1), MgCl₂ (0.11), VB₁ (0.05), VB₂ (0.05), CaCl₂ (1.5), corn bran (6), and a water–materials ratio of 100%. The fermentation condition was as follows: inoculum volume of 5.5% (v/w), rice weight of 50 g in one bowl with a diameter of 120 mm and a depth of 90 mm, incubation temperature of 26 °C, and incubation time of seven days. Under the optimized condition, the maximal C. militaris polysaccharide content and free radical scavenging ratio were 68.3 mg/g dry substrate and 98.9%, respectively. This study provides a new strategy for the production of healthy food from traditional food.

Lignin peroxidase (LiP) is the primary enzyme responsible for lignin degradation. In our previous work, in order to shorten the pretreatment time and increase the lignin degradation, we have pretreated the corn stalk (CS) using a combination of Aspergillus oryzae CGMCC 5992 solid-state fermentation and H2O2 treatment. In the present study, one-factor-at-a-time design and response surface design were applied to optimize the nutritional constituents for LiP production in liquid-state fermentation by A. oryzae CGMCC 5992 and the conditions for CS degradation by A. oryzae CGMCC 5992. The optimal medium included CS of 30 g/L, glucose of 4.6 g/L, sodium nitrate of 1.2 g/L, corn steep liquor of 1 g/L, yeast extract of 1.2 g/L, and vitamin B1 of 0.15 g/L. Under these optimal conditions, the LiP production reached its maximum of 652.34 U/L. The optimal condition for CS degradation included CS of 20 g, A. oryzae CGMCC 5992 broth of 50 mL, 1.5 % H2O2 solution of 80 mL, H2O2 flow rate of 0.4 mL/min, water volume of 240 mL (water/material ratio of 12:1), hydrolysis temperature of 39 °C, and hydrolysis time of 8 h. Before hydrolysis, CS and water were pretreated at 113 °C for 11 min. Under these optimal conditions, the sugar yield reached its maximum of 46.28 %. Our newly developed method had great advantages in pretreatment of CS due to its quickness, convenience, safety, no special equipment and high sugar yield.