Application of response surface methodology in medium optimization for pyruvic acid production of <Emphasis Type="Italic">Torulopsis glabrata</Emphasis> TP19 in batch fermentation

Response surface methodology （RSM） was used to optimize the fermentation medium for enhancing pyruvic acid production by Torulopsis glabrata TP19. In the first step of optimization, with Plackett-Burman design, ammonium sulfate, glucose and nicotinic acid were found to be the important factors affecting pyruvic acid production significantly. In the second step, a 23 full factorial central composite design and RSM were applied to determine the optimal concentration of each significant variable. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the critical components were obtained as follows： ammonium sulfate 0.7498 （10.75 g/L）, glucose 0.9383 （109.38 g/L） and nicotinic acid 0.3633 （7.86 mg/L） with a predicted value of maximum pyruvic acid production of 42.2 g/L. Under the optimal conditions, the practical pyruvic acid production was 42.4 g/L. The determination coefficient （R^2） was 0.9483, which ensures adequate credibility of the model. By scaling up fermentation from flask to jar fermentor, we obtained promising results.     

Effects of α-tocopheryl acetate supplementation in preslaughter diet on antioxidant enzyme activities and fillet quality of commercial-size Sparus macrocephalus

This study examined the effects of dietary α-tocopheryl acetate supplementation on antioxidant enzyme activities and fillet quality in commercial-size Sparus macrocephalus. Three hundred fish [main initial weight （350±12） g] were divided into three groups （E250, E500 and El000） and reared in 9 cages. The fish were fed for 8 weeks with three diets containing different levels of dietary α-tocopheryl acetate （289, 553, 1069 mg/kg）. Over the experimental period, fish were fed to satiation and reached a final mean weight of （465±28） g without significant body weight difference and proximate composition difference. Fillet α-tocopherol was significantly （P〈0.05） different between groups, reaching levels of 14.2, 22.1, 30.9 pg/mg fillet for groups E250, E500 and El000, respectively. Total serum superoxide dismutase （SOD） activity increased significantly （P〈0.05） in fish fed the diets high in α-tocopheryl acetate, but serum glutathione peroxidase （GPX） activity was unaffected. In storage on ice, fillets of fish fed the diets high in α-tocopheryl acetate exhibited significantly lower （P〈0.05） levels of oxidation. These results suggested that increased dietary α-tocopheryl acetate could increase its flesh deposition, increase the activity of SOD and prevent lipid peroxidation ofSparus macrocephalus fillets in retail storage on ice.     

趋向义"上"和继续义"上"的对比分析

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对比教学中的六大“对比点”

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浅谈如何在一日活动中渗透数学教育

《幼儿园教育指导纲要》指出:"能从生活和游戏中感受事物的数量关系并体验到数学的重要和有趣."日常生活活动在小班幼儿的一日活动中占了很大的比例,小班幼儿由于年龄和生理心理特点,如果将数学知识融入生活中,让幼儿在生活中学数学,就既可满足幼儿的需要,又可很好地完成数学教学目标.在组织小班数学活动时,我着手进行数学知识与生活、游戏相结合的实验,让幼儿在生活中学数学.     

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我出世时,因为缺氧造成了小脑瘫痪。从那时起,我的人生便被涂抹上了一层淡淡的灰色。然而我并不像其他脑瘫孩子那样可怜,母爱无限的力量让我的童年充满了阳光,开放得像夏花一样绚烂!母亲,一个多么神圣的称谓!她和天使一样美丽、温暖。然而母亲又是艰辛的,尤其是一个残疾孩子的母亲,要承受的心理压力和磨难是常人难以想象的,所以,就是用再好的字眼也无法抒发我内心深处对妈妈最真挚的情感。坎坷的命运使我们母子学会了坚强。在我小的时候,妈妈看见别的孩子都能自由地行走,而被病魔缠绕的我柔弱得连坐都坐不住,内心非常焦急。她带着我四处求医…     

飘飞的红纸条

文昌阁里飘飞的红纸条在初三1班引起了一场轩然大波,郭立恒作为班长竟然也相信封建迷信!面对同学们的议论．班长的心莫名地慌乱起来,他决定亲自到文昌阁弄个水落石出!事情果真如此吗?     

毛毛虫怎样过河

杨扬是一所普通学校的普通学生,由于名字的原因,他和另外两个与自己同姓同名的“杨扬”发生了一系列让人意想不到的好玩故事,从而彻底改变了杨扬的生活。     

物理中考试题的新走向

随着课标的颁布实施,各地对物理中考命题进行了不同程度的改革尝试和有益的探索。物理中考试题体现了课标的理念以及知识与技能、过程与方法、情感态度与价值观的三维课程目标,加强了对基础知识、应用和实验能力以及同学们科学思想、科学精神、科学方法、科学能力和科     

美术教学中培养学生的联想能力

小学美术教学大纲指出:"通过美术教学,培养学生的观察能力、形象记忆能力、想象能力和创造能力。"要培养学生的想象能力,