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71.
Separate sample logistic discrimination 总被引:8,自引:0,他引:8
72.
Veeresh Juturu 《Critical reviews in biotechnology》2016,36(6):967-977
Lactic acid is an important platform chemical for producing polylactic acid (PLA) and other value-added products. It is naturally produced by a wide spectrum of microbes including bacteria, yeast and filamentous fungi. In general, bacteria ferment C5 and C6 sugars to lactic acid by either homo- or hetero-fermentative mode. Xylose isomerase, phosphoketolase, transaldolase, l- and d-lactate dehydrogenases are the key enzymes that affect the ways of lactic acid production. Metabolic engineering of microbial strains are usually needed to produce lactic acid from unconventional carbon sources. Production of d-LA has attracted much attention due to the demand for producing thermostable PLA, but large scale production of d-LA has not yet been commercialized. Thermophilic Bacillus coagulans strains are able to produce l-lactic acid from lignocellulose sugars homo-fermentatively under non-sterilized conditions, but the lack of genetic tools for metabolically engineering them severely affects their development for industrial applications. Pre-treatment of agriculture biomass to obtain fermentable sugars is a pre-requisite for utilization of the huge amounts of agricultural biomass to produce lactic acid. The major challenge is to obtain quality sugars of high concentrations in a cost effective-way. To avoid or minimize the use of neutralizing agents during fermentation, genetically engineering the strains to make them resist acidic environment and produce lactic acid at low pH would be very helpful for reducing the production cost of lactic acid. 相似文献
73.
Wei Yue Qian-liang Ming Bing Lin Khalid Rahman 《Critical reviews in biotechnology》2016,36(2):215-232
The development of plant tissue (including organ and cell) cultures for the production of secondary metabolites has been underway for more than three decades. Plant cell cultures with the production of high-value secondary metabolites are promising potential alternative sources for the production of pharmaceutical agents of industrial importance. Medicinal plant cell suspension cultures (MPCSC), which are characterized with the feature of fermentation with plant cell totipotency, could be a promising alternative “chemical factory”. However, low productivity becomes an inevitable obstacle limiting further commercialization of MPCSC and the application to large-scale production is still limited to a few processes. This review generalizes and analyzes the recent progress of this bioproduction platform for the provision of medicinal chemicals and outlines a range of trials taken or underway to increase product yields from MPCSC. The scale-up of MPCSC, which could lead to an unlimited supply of pharmaceuticals, including strategies to overcome and solution of the associated challenges, is discussed. 相似文献
74.
Sudip Chakraborty Handajaya Rusli Arijit Nath Jaya Sikder Chiranjib Bhattacharjee Stefano Curcio 《Critical reviews in biotechnology》2016,36(1):43-58
Biocatalytic membrane reactors have been widely used in different industries including food, fine chemicals, biological, biomedical, pharmaceuticals, environmental treatment and so on. This article gives an overview of the different immobilized enzymatic processes and their advantages over the conventional chemical catalysts. The application of a membrane bioreactor (MBR) reduces the energy consumption, and system size, in line with process intensification. The performances of MBR are considerably influenced by substrate concentration, immobilized matrix material, types of immobilization and the type of reactor. Advantages of a membrane associated bioreactor over a free-enzyme biochemical reaction, and a packed bed reactor are, large surface area of immobilization matrix, reuse of enzymes, better product recovery along with heterogeneous reactions, and continuous operation of the reactor. The present research work highlights immobilization techniques, reactor setup, enzyme stability under immobilized conditions, the hydrodynamics of MBR, and its application, particularly, in the field of sugar, starch, drinks, milk, pharmaceutical industries and energy generation. 相似文献
75.
从多管水母属A equoren v ictu ria 分离出的绿色荧光蛋白(GFP) , 因其特有的生物化学性质及该基因在异源细胞内的表达产物亦能产生强烈的绿色荧光, 使其在现代细胞生物学和分子生物学研究领域的应用具有广阔前景。本文就其研究进展及其应用进行简要综述。 相似文献
76.
本文结合胡杨盐诱导基因和盐抑制基因的筛选,介绍了差减杂交(subtractivehybridization)技术的试验原理,设计思想和应用方法。 相似文献
77.
溶葡球菌酶(lysostaphin,Lys)是采用基因克隆技术使溶葡球菌酶基因实现外源表达所产生的蛋白质。它是Zn2+依赖的金属蛋白酶,具有肽链内切酶活性,能专一性地水解葡萄球菌细胞壁Gly五肽桥联,使金黄色葡萄球菌(特别是MRSA)细胞壁破裂,达到溶菌杀菌作用,而不产生耐药性。作为一种抗菌剂,在兽药与临床等领域具有巨大的应用潜力。综述对溶葡球菌酶的来源、作用机制、不同表达系统及前景与展望进行综述。 相似文献
78.
Masoomeh Etehadnia Doug R. Waterer Karen K. Tanino 《Journal of Plant Growth Regulation》2008,27(4):331-341
The phytohormone abscisic acid (ABA) has been proposed to act as a mediator in plant responses to a range of stresses, including
salt stress. Most studies of ABA response apply ABA as a single dose. This may not resemble the prolonged increasing endogenous
ABA levels that can occur in association with slowly increasing salinity stresses in nature or field situations. Salt stress
response based on method of ABA application was examined in four potato genotypes of varying salt stress resistance: the sensitive
ABA-deficient mutant and its normal sibling, a resistant genotype line 9506, and commercial cultivar ‘Norland’ of moderate
resistance. ABA was applied by root drench at 0, 50, 75, or 100 μM concentrations through a single dose, or by slowly increasing
multiple ABA doses in a sand-based growing system under greenhouse conditions. Salt tolerance was then evaluated after 2 weeks
of exposure to 150–180 mM NaCl stress. The method of ABA application had a marked effect on the responses to salt stress.
Plant responses to the method of ABA application were differentiated according to (1) growth rate, (2) root water content,
and (3) apparent shoot growth response. Under a single dose, growth rate increased in all genotypes under salt stress, whereas
slowly increasing multiple ABA applications generally maintained stable growth rates except in the ABA-deficient mutant where
there was an upward growth trend. Percent root water content was elevated only under slowly increasing multiple ABA doses
in two genotypes, whereas none of the single-dose treatments induced any change. The single ABA dose enhanced vertical growth,
whereas the slowly increasing multiple ABA dose applications enhanced lateral shoot growth. Because exogenous application
is still an artificial system, endogenous ABA was supplied through grafting of ABA-deficient mutant scions onto rootstocks
with known elevated ABA levels. Multiple exogenous ABA applications as low as 50 μM elicited similar shoot water content responses
as grafting treatments without ABA application in the mutant genotype but had no effect on the ABA normal sibling. Shoot dry
weight was significantly increased through grafting over all exogenous ABA treatments. Our study further indicates that the
method of ABA application regime in itself can alter plant responses under salt stress and that certain application regimes
may reflect responses to elevated endogenous levels of ABA. 相似文献
79.
长期施磷对黄壤旱地磷库变化及地表径流中磷浓度的影响 总被引:20,自引:1,他引:19
对贵州黄壤旱地进行采样以及盆栽试验,探索黄壤旱地磷库的变化及其对地表径流磷量的影响。结果表明,长期施磷后黄壤旱地无机磷占全磷的比例逐渐增高,Al-P、Fc-P和Ca-P积累的顺序为Fe-P>Al-P>Ca-P。长期施磷后黄壤旱地的有效磷和藻类可利用的总磷也不断积累,高磷(Olsen-P>25mg·kg^-1)旱地藻类可利用的总磷与Al-P、Fe-P和Ca-P的相关系数分别为0.859、0.903和0.650,Fc-P对藻类可利用磷量的影响起着最重要的作用。在模拟雨强为63.2mm·h^-1下,降雨30min后,低磷黄壤旱地(Olsen-P为4.62-15.9mg·kg^-1)径流中磷酸根磷含量仅为2.81-4.17μg·L^-1,生物有效性磷含量为0.723-0.876mg·L^-1;高磷黄壤旱地(Olsen-P)为29.4-59.2mg·kg^-1)径流中磷酸根磷含量达到0.026-0.714mg·L^-1,生物有效性磷含量增加到0.996-1.281mg·L^-1;高磷黄壤旱地地表径流磷量能加速水体富营养化的产生。 相似文献
80.