Enhanced production of isoamyl acetate from beet molasses with addition of fusel oil by Williopsis saturnus var. saturnus

Fusel oil which contains high level of amyl alcohols (approximately 45–55%) is a by-product obtained from the distillation of alcohol made by fermentation of molasses. Williopsis saturnus is a yeast which is able to convert isoamyl alcohol into isoamyl acetate. The aim of this study was to increase the formation of isoamyl acetate by the addition of fusel oil at the ratios of 1%, 2% and 3% (v/v) to molasses based fermentation medium using W. saturnus. It was found out that bioconversion of added fusel oil into isoamyl acetate was possible and an addition of 1% fusel oil led to an increase in isoamyl acetate concentration from 118 to 354 mg/L.     

煤生物转化产物作为水煤浆添加剂试验研究

本项研究通过培育微生物菌种,作用于经硝酸处理的褐煤样,得到煤生物转化产物.用此水溶性产物作为添加剂制备出水煤浆,与加与不加常规添加剂的两种水煤浆进行粘度对比试验,从考察了煤生物转化产物制备的水煤浆流变特性.结果显示使用煤生物转化产物作为水煤浆添加剂能制备出优质水煤浆.     

生物转化法生产L－苹果酸的研究（Ⅰ）──富马酸酶产生菌株的筛选

经对３０余份采自不同地区土样的菌种筛选，得到２０株可将富马酸转化为Ｌ－苹果酸的菌株，其中尤以Ｇ（０４）株的转化活力最高。对该菌株的较佳转化条件研究表明：较适的转化温度为３７℃，基质初始ｐＨ值为７．５。菌体经０．２％胆酸３８℃处理２０ｈ，可使富马酸转化率较未处理的对照提高７４．３％。另外，采用０．２％胆酸或０．０６％ＴＰＣ处理菌体，均可在转化反应中抑制琥珀酸副产物的形成。     

马来酸合成L－苹果酸产酶株的筛选

通过对６０余份采自不同地区的土样进行菌种筛选，得到１１株可将马来酸转化为Ｌ－苹果酸的菌株。其中尤以１１Ｂ５Ａ株的转化活力最高。对该菌株的较佳转化条件研究表明：摇瓶菌体培养时间以２４ｈ为好；培养基的较适初始ｐＨ值为７．０；转化液中添加２－巯基乙醇、甲苯或菌体经胆酸或ＤＬ－苹果酸预处理后再用于转化，均会不同程度地提高细胞的转化活力。     

Bioconversion of n−3 and n−6 PUFA by <Emphasis Type="Italic">Clavibacter</Emphasis> sp. ALA2

Clavibacter sp. ALA2 oxidized n−3 and n−6 PUFA into a variety of oxylipins. Structures of products converted from EPA and DHA were determined as 15,18-dihydroxy-14,17-epoxy-5(Z),8(Z),11(Z)-eicosatrienoic acid and 17,20-dihydroxy-16,19-epoxy-4(Z),7(Z),10(Z),13(Z)-docosatetraenoic acid by GC-MS and NMR analyses. In contrast, γ-linolenic acid and arachidonic acid were converted to diepoxy bicyclic FA, tetrahydrofuranyl monohydroxy FA, and trihydroxy FA. Thus, the structures of bioconversion products were different between n−3 and n−6 PUFA. Furthermore, strain ALA2 placed hydroxy groups and cyclic structures at the same position from the ω-terminal despite the number of carbons in the chain and the double bonds in the PUFA.     

Conversion of oleic acid to 10-ketostearic acid by aStaphylococcus species

In the course of using microorganisms to produce value-added products from soybean oil or its fatty acids, a culture contaminant was isolated and tentatively identified as aStaphylococcus species. This microorganism converts oleic acid (cis-9-octadecenoic acid) to 10-ketostearic acid (10-keto-octadecanoic acid) in growing cultures. Bioconversion was studied in two different media at temperatures from 30 to 41°C, with shaking at 150 rpm. Cells were grown in 50 mL of media for 24 h and then incubated with 0.25 g oleic acid for 24 h. Optimum conditions have allowed better than 90% conversion with 85% recovery. Unreacted oleic acid and 10-hydroxystearic acid (10-hydroxyoctadecanoic acid) are the only other compounds present in the ethyl ether extract of the fermentation broth.     

苜蓿黄酮的分离及其生物转化研究进展

苜蓿属植物资源丰富,并且含有大量的黄酮类物质。黄酮类物质具有多种生物活性及药理作用。本文对苜蓿黄酮的分离、结构鉴定以及黄酮苷的生物转化的最新进展等进行了总结,并对苜蓿黄酮的发展方向进行了探讨。     

农林废弃物的高效生物利用

介绍农林废弃物高效生物利用的几条主要途径,生物技术在农林废弃物的利用领域有着广阔的前景。