We examined butanol fermentation by Clostridium beijerinckii NCIMB 8052 using various hydrolyzates obtained from rice bran, which is one of the most abundant agricultural by-products in Korea and Japan. In order to increase the amount of fermentable sugars in the hydrolyzates of rice bran, various hydrolysis procedures were applied. Eight different hydrolyzates were prepared using rice bran (RB) and defatted rice bran (DRB) with enzyme or acid treatment or both. Each hydrolyzate was evaluated in terms of total sugar concentration and butanol production after fermentation by C. beijerinckii NCIMB 8052. Acid treatment yielded more sugar than enzyme treatment, and combined treatment with enzyme and acid yielded even more sugars as compared with single treatment with enzyme or acid. As a result, the highest sugar concentration (33 g/l) was observed from the hydrolyzate from DRB (100 g/l) with combined treatment using enzyme and acid. Prior to fermentation of the hydrolyzates, we examined the effect of P2 solution containing yeast extract, buffer, minerals, and vitamins on production of butanol during the fermentation. Fermentation of the hydrolyzates with or without addition of P2 was performed using C. beijerinckii NCIMB 8052 in a 1-l anaerobic bioreactor. Although the RB hydrolyzates were able to support growth and butanol production, addition of P2 solution into the hydrolyzates significantly improved cell growth and butanol production. The highest butanol production (12.24 g/l) was observed from the hydrolyzate of DRB with acid and enzyme treatment after supplementation of P2 solution.

The purpose of this study was to investigate the antioxidant and skin whitening effects of Artemisia iwayomogi extract. Artemisia iwayomogi was extracted with 100% ethanol and water. The antioxidative and skin whitening effects of these extracts were determined with in vitro assays by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) method assessing the inhibitory effects on tyrosinase activity and melanogenesis in B16 melanoma cells. Radical scavenging activity of the extracts was tested by DPPH assay which showed a high DPPH radical scavenging activity (SC 50 ; 17.1 ppm in EtOH, 198.4 ppm in water). In term of tyrosinase inhibitory activity, Artemisia iwayomogi ethanol extract showed high inhibition activity (IC 50 : 481.8 ppm). In B16 mouse melanoma cells, the ethanol extract significantly inhibited melanin synthesis by 36.8% at a concentration of 50 ppm. These results suggest that Artemisia iwayomogi ethanol extract has significant antioxidant activity and whitening activity.