An integrated biore ﬁ nery concept for conversion of sugar beet pulp into value-added chemicals and pharmaceutical intermediates-猫眼课题宝

将甜菜浆转化为增值化学品和医药中间体的综合生物炼制概念

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Max Cárdenas‐Fernández;Maria Bawn;Charlotte Hamley;Penumathsa K. V. Bharat;Fabiana Subrizi;N. Suhaili;David P. Ward;Sarah Bourdin;P. Dalby;H. Hailes;P. Hewitson;S. Ignatova;C. Kontoravdi;D. Leak;N. Shah;T. Sheppard;J. Warda;G. Lye

英国每年种植的甜菜超过800万吨。甜菜浆(SBP)是甜菜加工过程中的主要副产物，目前作为低价饲料进行干燥和销售。SBP是碳水化合物的丰富来源，主要以纤维素和果胶的形式存在，包括D-葡萄糖(Glu)、L-阿拉伯糖(Ara)和D-半乳糖醛酸(GalAc)。这项工作描述了集成BioreﬁNery概念的技术可行性，用于SBP的分级和将这些单糖转化为附加值产品。SBP分级最初是在温和的条件下通过蒸汽爆炸进行的，以产生可溶的果胶和不溶的纤维素馏分。纤维素很容易被纤维素酶水解，释放出谷氨酸，然后由商业酵母菌株发酵，以高产量生产生物乙醇。果胶组分既可以使用物理化学方法完全水解，也可以使用克隆的阿拉伯酸酶和半乳糖醛酸酶选择性地水解，以产生富含Ara和GalAc的溪流。这些单体可以使用离心层析法或超ﬁ滴定法分离成适合后续酶促升级的流。根据转酮醇酶(TK)和转氨酶()的使用经验，探索了将Ara和GalAc转化为高附加值产品的方法。特别描述了利用突变体TK将阿糖胞苷转化为L-葡萄糖七糖(GluHep)，该糖在低血糖和癌症方面具有潜在的治疗应用。与的初步研究还表明，GluHep可以选择性地胺化成相应的手性氨基多元醇。目前的工作是对剩余的SBP单体GalAc进行升级，并对BioreﬁNery概念进行建模，以实现经济和生命周期分析。数据点代表实际的实验设计点。采用中心组合设计，在不同时间和不同操作压力下进行11次SE前处理。SE实验是在搅拌式PARR加压反应器中进行的(1 L容量，波士顿仪器)，在搅拌ﬁ为150rpm的情况下，在规定的压力和时间下洗涤SBP 50g。(Ara)L-阿拉伯糖、(Gal)D-半乳糖和(GA)D-半乳糖醛酸。采用250mL半制备型CPC色谱柱(Kromaton)，以乙醇：硫酸铵(300g L(CID：4)1)(0.8：1.8V/V)为相体系，以1000rpm的转速上升，流动相ﬂ为8mLmin(CID：4)1。固定相保留率为50%。使用转氨酶对剩余的GalAc组分进行立体选择性胺化，包括Vioraceum u-。初步研究表明，该酶可将GalAc转化为6-氨基-2，3，4，5-四羟基己酸，可用于合成聚羟基聚酰胺34等生物聚合物，并可作为有效抗病毒的聚羟基氮杂环己烷的前体。本研究所用的三种酶(AF、TK和)已在大肠杆菌中表达，在稀释甜菜醋上生长时能产生较高的-c酶活性。未来的研究将解决与集成SBP BioreNery概念相关的一些主要工程挑战。这些都是摘要

Over 8 million tonnes of sugar beet are grown annually in the UK. Sugar beet pulp (SBP) is the main by-product of sugar beet processing which is currently dried and sold as a low value animal feed. SBP is a rich source of carbohydrates, mainly in the form of cellulose and pectin, including D -glucose (Glu), L -arabinose (Ara) and D -galacturonic acid (GalAc). This work describes the technical feasibility of an integrated biore ﬁ nery concept for the fractionation of SBP and conversion of these monosaccharides into value-added products. SBP fractionation is initially carried out by steam explosion under mild conditions to yield soluble pectin and insoluble cellulose fractions. The cellulose is readily hydrolysed by cellulases to release Glu that can then be fermented by a commercial yeast strain to produce bioethanol at a high yield. The pectin fraction can be either fully hydrolysed, using physico-chemical methods, or selectively hydrolysed, using cloned arabinases and galacturonases, to yield Ara-rich and GalAc-rich streams. These monomers can be separated using either Centrifugal Partition Chromatography (CPC) or ultra ﬁ ltration into streams suitable for subsequent enzymatic upgrading. experience with transketolase (TK) and transaminase (TAm) enzymes, the conversion of Ara and GalAc into higher value products was explored. In particular the conversion of Ara into L - gluco -heptulose (GluHep), that has potential therapeutic applications in hypoglycaemia and cancer, using a mutant TK is described. Preliminary studies with TAm also suggest GluHep can be selectively aminated to the corresponding chiral aminopolyol. The current work is addressing the upgrading of the remaining SBP monomer, GalAc, and the modelling of the biore ﬁ nery concept to enable economic and Life Cycle Analysis (LCA). data points represent actual experimental design points. 11 SE pretreatments over various times and operating pressures were performed using a central composite design. SE experiments were carried out in a stirred Parr pressure reactor (1 L capacity, Boston Instruments) with 50 g of whole and washed SBP at the speci ﬁ ed pressure and time with agitation ﬁ xed at 150 rpm. (Ara) L -arabinose, (Gal) D galactose and (GA) D -galacturonic acid. Experiments were performed using a 250 mL semi-preparative CPC column (Kromaton), using an ethanol : ammonium sulphate (300 g L (cid:4) 1 ) (0.8 : 1.8 v/v) phase system at 1000 rpm in ascending mode, with a mobile phase ﬂ ow rate of 8 mL min (cid:4) 1 . Stationary phase retention was 50%. the stereoselective amination of the remaining GalAc fraction using transaminases including the C. violaceum u -TAm. Initial studies have suggested that this enzyme can convert GalAc into 6-amino-2,3,4,5-tetrahydroxyhexanoic acid which can be used for the synthesis of biopolymers such as polyhydroxypolyamides 34 and as a precursor for potent antiviral polyhydroxyazepanes. 35 Three of the enzymes used in this study (AF, TK and TAm) have been expressed in E. coli which can yield high speci  c enzyme activities when grown on diluted sugar beet vinasse. Future studies will address some of the major engineering challenges associated with the integrated SBP biore  nery concept. These are summarised

An integrated biore ﬁ nery concept for conversion of sugar beet pulp into value-added chemicals and pharmaceutical intermediates

将甜菜浆转化为增值化学品和医药中间体的综合生物炼制概念

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