Biosynthesis of biotin-vitamers by family Enterobacteriaceae

The biosynthesis of biotin-vitamers from various carbon sources by the members of the Enterobacteriaceae as one of the groups of intestinal bacteria was investigated. The biotin-vitamers synthesized in each case included one or more of dethiobiotin (main product), 7-keto-8-aminopelargonic acid, and biotin. True biotin was shown to be synthesized under aerobic conditions but not under anaerobic conditions by each of several strains belonging to one of the genera, Erwinia, Escherichia, Proteus, and Serratia, and using culture media containing one of galactose, peptone, Polypepton, or casamino acid. In addition, a biotin precursor, pimelic acid, was also synthesized by several bacteria utilizing carbon sources such as maltose, mannose, galactose, peptone, or casamino acid.     

Biosynthesis of biotin-vitamers from unsaturated higher fatty acids by bacteria

The biosynthesis of biotin-vitamers from unsaturated higher fatty acids by the resting cell system of bacteria was investigated. Biotin-vitamer formation from oleic, linoleic and linolenic acids was found in certain bacteria belonging to the genera Enterobacter, Agrobacterium, Bacillus, Escherichia and Micrococcus. The biotin-vitamers were identified as a mixture of 7,8-diaminopelargonic acid, desthiobiotin and biotin. Metabolites other than biotin-vitamers from those fatty acids were analyzed by gas-liquid chromatography and mass spectrometry. Linoleic, oleic, C-17 and C-15 saturated fatty acids were identified as the main metabolites of linolenic acid. The pathway of biosynthesis of pimelic acid from linolenic acid by a strain of Bacillus sphaericus AKU 0227 was also studied.     

化妆品微生物检测结果分析

目的提高化妆品的卫生质量与使用的安全性,为加强对化妆品生产企业和销售商的卫生监督提供依据.方法按<化妆品卫生规范>卫法监发(2002)229号对深圳市化妆品生产企业和销售商随机抽检和部分送样进行检测.结果共检测3 290份化妆品,合格产品3 201份,合格率为97.3%,其中检出菌落总数、霉菌和酵母菌、粪大肠菌群超标份数分别为70、81、8份,超标率各为2.13%、2.46%、0.24%,在检测的样品中未检出绿脓杆菌、金黄色葡萄球菌.结论该市化妆品的卫生质量较好,但仍有部分化妆品存在不同程度的微生物污染,建议加强对化妆品原材料和化妆品生产过程关键岗位的卫生监督.     

Microbiological monitoring of water ecosystems

The paper presents the results of a study of the microbial community of the Lena River. Active anthropogenic pollution induces structural changes in the microbiocenoses of aquatic objects and increases in the quantity of opportunistic gram-negative microorganisms and in that of antibiotic-resistant bacteria.     

Microbiological quality of desiccated coconut

A microbial survey of Sri Lankan desiccated coconut has been made on material purchased in supermarkets in Sheffield or on material obtained directly from the processing company. The total viable count (TVC) was reduced by spoilage and pasteurization from 10(4)/g to 10(3)/g. Most samples contained low levels of coagulase-positive Staphylococcus aureus suggesting that this commodity had been handled during production. One focus of contamination with Aspergillus flavus was found for each 8.34 g of desiccated coconut (mean contamination). The number of bacteria and moulds in spoiled coconut was significantly lower than that in coconut obtained from the processor or purchased from retail outlets. It is suggested that the accumulation of free fatty acids, aliphatic methyl ketones and secondary alcohols produced during fungal spoilage has had a bactericidal and fungicidal effect. The use of microbial specifications for foods is questioned in situations where there is evidence of microbial spoilage having taken place.