Rhodobacter sphaeroides is a purple non-sulfur photosynthetic bacteria that participates in the anoxic cycling of carbon both as the primary producer and as the light-stimulated consumers of the reduced organic compounds. In this study, six different organic acids, i.e. acetate, lactate, oxaloacetate, malate, succinate, and citrate, were selected and used to analyze the relationships between the organic acid source and the cell growth. The C 4 compound exhibited an enhanced cell growth compared to the other organic acids, and the growth rate of R. sphaeroides that was grown with 0.03 M succinic acid was significantly 3.2-fold faster than the C 6 compound of 0.03 M citrate. Additionally, the cell growth of R. sphaeroides was enhanced with increasing light intensity, and the growth rate and the dry cell weight of R. sphaeroides that were grown under the light conditions of 15 W/m 2 were 2.0-and 1.2-fold higher than R. sphaeroides at 3 W/m 2 . Therefore, the high light intensity probably affected the growth of R. sphaeroides. Moreover, the bluecolored light emitting diode (LED) exhibited a highest growth rate and cell concentration of R. sphaeroides among the various types of LEDs, and the enhanced cell growth phenomenon under the blue LED conditions was dramatically stimulated at low concentrations of succinic acid, which was compensatory for succinic acid. Therefore, a high light intensity and a blue LED as the light source were necessary for the enhanced cell growth for the C 4 organic acid, i.e. succinic acid.

Introduction Edible mushrooms, a valuable source of bioactive compounds and nutrients, have been consumed as part of the diet in some countries for thousands of years. They are quite high in protein, carbohydrate and fibre and low in fat content with low trans-isomers of unsaturated fatty acids. In addition, they also have many components such as triterpenes, phenolic compounds, chitosan, eritadenine, sterols (such as ergosterol), triterpenes, etc., which are considered momentous agents for some hitherto unknown healthy properties. Recently, edible mushrooms have become increasingly attractive as functional foods and medicines to treat diseases including cancer, diabetes, inflammation and ache due to the presence of these active components. Pain is an unpleasant sensation, which is a typical response to an untoward event associated with tissue damage, such as injury and inflammation. The aims of this review are to report the positive analgesic effect of several edible mushrooms on pain and its relevant active constituents. Conclusion In our review, the edible mushrooms including Pleurotus pulmonarius, Agaricus brasiliensis, Agaricus bisporus var. hortensis, Agaricus macrosporus, Coriolus versicolor and Cordyceps sinensis have been investigated that possess antinociceptive and antiinflammatory effects owing to their bioactive components such as β-glucan, agaricoglyceride A, polysaccharopeptide and cordymin as well as other active components. What is more, there are barely any side effects caused by the toxicity of edible mushrooms in vitro and in vivo. However, further research is required with clinical trials and applications.