The research objective was to determine the occurrence of indigenous yeasts from napa cabbage (Brassica rapa subsp. pekinensis) wastes that potential in ethanol fermenting activity at stress condition such high concentration of glucose and ethanol. Indigenous yeasts were isolated from 1 g napa cabbage wastes and identified with RapID Yeasts Plus System. Glucose and ethanol tolerance was assessed by growing yeasts in modified Nutrient Broth/NB (Oxoid Ltd.) added with 10%, 20%, and 30% of glucose monohydrates or 10%, 15%, and 20% of ethanol concentration and measuring the optical density (OD) every 24 h until 72 h. The best isolates tested to ferment napa cabbage wastes were mixed with water (1:1.5) then the ethanol contents analyzed by dichromate oxidation method. Results showed that there are two potential ethanol-fermenting indigenous yeasts isolated from napa cabbage wastes which identified as Hanseniaspora guilliermondii and Candida krusei. Both yeasts have the ability to survive at 30% of glucose concentration until 72 h incubation, though the highest growth was reached at 10% of glucose concentrations for 24 h incubation. The yeasts growth in high ethanol concentration tends to decrease after 48 h for C. krusei and 24 h for H. guilliermondii. The highest ethanol production from napa cabbage fermentation showed that mixed culture (1:1) of C. krusei and H. guilliermondii with 1.43% ethanol contents for 24 h incubation.
Objectives of the research were to determine the best combination of mozzarella cheese whey and sugarcane molasses as agro-industrial wastes in producing bioethanol with the inoculation of indigenous yeasts. The research has been done experimentally by Completely Randomized Design (CRD) 3 × 3 factorial pattern, and the data was analyzed with ANOVA then continued with Tukey test. Treatments consisted of two factors, i.e. addition of sugarcane molasses (10%, 15%, 20%) and indigenous yeasts combination [C. tropicalis 1 + Blast. capitatus + C. tropicalis 2 (1:1:1), C. tropicalis 1 + Blast. capitatus (1:1), C. tropicalis 1 + C. tropicalis 2 (1:1)] that were replicated three times. Substrates fermented at ambient (25-27 °C) for 24 hours, then the bioethanol contents tested with chromium dichromate oxidation. Results show that the treatment combination of sugarcane molasses concentration and indigenous yeasts combination and single treatments of indigenous yeasts combination have shown significant effects towards the bioethanol contents, meanwhile the treatments of molasses concentration has shown nonsignificant effects. The best bioethanol contents (8.49%) was gained by the treatment combination of 15% sugar cane molasses concentration with the inoculation of C. tropicalis 1 + Blast. capitatus (1:1).
Aims of the research was to determine the best dilution ratio of Tacca leontopetaloides with the combination of indigenous yeasts in producing bioethanol. The research methodology was experimental with Completely Randomized Design (CRD) 3 × 3 factorial pattern, ANOVA used to analyze the data then the significant treatment continued with Tukey test. The treatments was two factors i.e. Tacca leontopetaloides dilution ratio with water (1:2, 1:3, 1:4) with indigenous yeasts combination C. natalensis + C. krusei + H. guilliermondii (1:1:1), C. natalensis + C. krusei (1:1), C. natalensis + H. guilliermondii (1:1) with three times replication. The diluted Tacca leontopetaloides was ferment at room temperatures (25-27 °C) for 48 hours and then tested with chromium dichromate oxidation method to determine the bioethanol contents. The results showed that mixed treatments of dilution ratio with indigenous yeasts combination and single treatments of dilution ratio gave significant effects towards bioethanol contents, while the combination of indigenous yeasts gave non-significant effects. The best treatments showed by the dilution ratio of 1:2 with the combination of C. natalensis and H. guilliermondii (1:1) that resulting in 3.46% of bioethanol.
石炭ガス化ガス中ヒ素およびセレンのSOFCアノード材中ニッケルへの影響を市販の熱力学平衡計算ソフトウェア，回分式反応器，デジタル顕微鏡を用いて検討した。0.5CO，0.2H2，0.04CO2，0.26N2，0.2H2O，10Ni，ヒ素，セレンの熱力学平衡計算は，10 ppm以上のヒ素存在下では固相のNiAsが生成，10-1000 ppmのヒ素およびセレン存在下では固相のNiAsと気相のAsSeが生成，1%以上のセレン存在下では固相のNi7Se8が生成する結果を示した。回分式反応器中模擬石炭ガス化ガス（H2/N2 = 30/70 vol%）雰囲気で500-900℃におけるヒ素およびセレン存在下でのニッケル線のインピーダンスをデジタルマルチメーターを用いて測定したところ，0.05 g以上のヒ素およびセレン存在下でニッケル腐食によりインピーダンスが増加した。回分式反応器およびデジタル顕微鏡においてヒ素およびセレンとニッケル板を模擬石炭ガス化ガス（CO/CO2/N2/H2 = 50.0/4.00/26.0/20.0 vol%）中900℃までで反応させたところ，Ni5As2の生成およびヒ素によるニッケルのポンピング現象により，ニッケル板表面上が腐食した。