Both in the laboratory and in industry it is necessary to have available for relatively long periods important strains (type strains or good producing agents).Previously,it was customary to maintain strains on slope agar (斜面) at low temperatures in the re...[继续阅读]

    Most mashing system in current use are classfied as infusion or decoction systems or a combination of both.In infusion mashing,using well-modified malt,the grain is fed into a mash tun,containing a filter-plate bottom,partially filled with hot water.The t...[继续阅读]

    The products of fermentation processes include gases,extracellular soluble molecules secreted into the fermentation broth and solid including cells containing intracellular soluble or insoluble molecules. Gases such as carbon dioxide and methane,produced ...[继续阅读]

    3. Transformation of Host Cells The ligated plasmid mixture is introduced into bacterial cells specially treated so that they take up DNA in a process termed transformation. In most cases E.coli is the preferred host with the advantages that calcium chlor...[继续阅读]

    Some enzymes are produced consititutively,that is,they are always made in substantial amounts when cells are growing.Other enzymes are inducible,that is,they are formed only in the presence of key substrates in the medium.The structural genes of inducible...[继续阅读]

    The process to recover starch from corn,known as wet-milling,is essentially a method of disrupting (破碎) the corn kernel (谷粒) in such a way that the component parts can be separated in an aqueous medium into relative pure fractions. Modern wetmilling of co...[继续阅读]

    A modified aerated STR(Stirred Tank Reactor,罐式搅拌反应器),the Frings acetator(Frings 醋化罐),is used in vinegar production,In this design,air is drawn in and distributed via a high-speed hollow-body turbin rotor,connected to an air suction pipe. The aerator is se...[继续阅读]

    The IUPAC rules for naming alcohols are as follows.These are rules for what are called substitutive names (The names such as methyl alcohol and ethyl alcohol are also approved by the IUPAC).Select the longest continuous carbon chain to which the hydroxyl ...[继续阅读]

    Enzymes are often used as nonrecoverable chemical reagents,in which case they are added to the substrate,incubated at the required temperature and pH for a period and subsequently destroyed. Amylase,proteases and other inexpensive bulk enzymes are used in...[继续阅读]

    The batch distillation process requires two (or,rarely,three) stills in series but is not an efficient process in terms of strength or purity of the ethanol produced . In the production of quality whiskies,brandies,rums,etc.the chemical inefficiency is a ...[继续阅读]