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On Pentose S U G a R S and Their Applications

On Pentose S U G a R S and Their Applications

In BIOCORE, VTT (Finland) are in- milk coagulant in cheese curd for- vestigating the production of xylitol mation. Xylonic acid has also been using . To this end, they have shown to be an excellent substitute developed high-performing yeast for gluconic acid in cement formula- strains that convert pres- tions, acting as a cement retardant, PARTNERS ent in biorefinery hydrolysates into providing better control of the setting xylitol in a single bioconversion ope- time. Interestingly, the setting time WORKING A biorefinery concept for the transformation of ration. More than 100 g L-1 xylitol of cement containing xylonic acid is biomass into 2nd generation fuels and have been produced at high rate two-fold shorter than that of cement ON and yield (0.7-0.8 g g-1) from the containing gluconic acid, underlining BIOCORE -rich stream, even the specific character of xylonic acid. though this contains high concen- Regarding other applications, xylonic trations of formic acid. Higher rates acid also figures in the top 30 buil- and titers are expected in less ding block chemicals from biomass, VTT (Finland) inhibitory hydrolysates, but are de- described by the US National Re- Contact: Merja Penttilä pendent on the xylose concentration newable Energy Laboratory, and has [email protected] TECHNICAL NOTE available. Residual in pen- been used as a precursor to synthe- Work focus: xylitol tose-rich stream provides energy for size 1,2,4-butanetriol. Moreover, and xylonic acid production the yeast, which also removes other the use of xylonic acid as precursor ON PENTOSE components from the hydrolysate, for the synthesis of polyamides has DLO (The Netherlands) thus facilitating the downstream been published. Nevertheless, des- Contact: Richard Gosselink processing. pite the potential of xylonic acid, only very limited commercial production [email protected] appears to exist at this time. Work focus: production and the development of a biobased diisocyanate AND THEIR In BIOCORE, scientists in VTT (Fin- land) have developed a yeast strain CIMV (France) for the production of high concentra- Contact : Bouchra Benjelloun APPLICATIONS tions of xylonic acid at low pH. More [email protected] than 140 g L-1 have been produced Work focus : biomass fractionation at pH 3, at a rate of ~1 g L-1 h-1. and C5-rich syrup production Xylonic acid Higher yields, titers and rates will Xylonic acid is a five- no doubt be achieved after further INRA (France) acid that naturally occurs in some process optimization. This strain also Contact : Isabelle Meynial Salles foodstuffs. In industrial foods xylonic performs well at higher pH, at which [email protected] acid could be used as a replacement even 170 g L-1 have been produced. Work focus : development of for gluconic acid, thus acting as a The host strain has an excellent tole- an isopropanol-producing strain latent acid in bakery products, an rance to most biomass hydrolysate acidulant in meat products, or as a inhibitors.

CONCLUSION

The development of biorefineries using advanced fractionation technologies, BIOCORE coordinator BIOCORE manager such as organosolv, to process lignocellulosic biomass holds the potential Michael O’Donohue Aurélie Faure to open up new valorization routes for pentose sugars. While significant INRA INRA Transfert R&D is still required to develop cost-efficient downstream processing [email protected] [email protected] of the pentose-rich syrup produced by CIMV, research performed by BIOCORE researchers is revealing how pure pentose sugars can be used to manufacture useful products. The BIOCORE project benefits from a budget of 20.3 million €, of which 13.9 million € represents aid from the European Union within http://www.biocore-europe.org the framework seven (FP7) research program under the grant agreement n°FP7-241566. EDITORIAL NOTE PENTOSES TODAY Furfural which the organic acids already Acid dehydration of D-xylose and L- present in the pentose syrup act as leads to the formation of catalysts for the formation of furfural The European FP7 project BIOCORE converting pentose sugars into use- Pentose sugars are primarily obtained sweeteners (Lenzing, Austria), a company furfural, an industrial chemical that (Figure 3), thus obviating the need for focuses on a lignocellulosic biorefi- ful products. In this technical note, from woody biomass and various crop that sources xylose from black liquor ari- was first produced by the Quaker the addition of mineral acids. So far, nery concept, which includes deri- some of BIOCORE’s results are residues. However, despite their humble sing from bisulfite pulping of beechwood. Oats Co. in Cedar Rapids, Iowa. As results reveal that the pentoses (pri- ving value from hitherto underused related in order to better visualize origins, the current market value of these In Asia, xylose is made from feedstocks, a chemical, furfural is used directly marily xylose mono- and oligomers) components, such as pentose how pentose-based products will two sugars is high (98% pure D-xylose such as coconut husks. China boasts many as a solvent or as an intermediate are effectively converted to furfural, sugars. To achieve this, BIOCORE form part of tomorrow’s bio-based sells for 2000 - 3000 € per ton), mainly xylose/xylitol producing facilities, although for the production of tetrahydrofu- with a yield greater than 50% and partners are devising a range of commercial products. because the production of these sugars is recently several of these have closed down ran, an important industrial solvent, a selectivity of 80% , which is better methods aimed at extracting and costly, and also because xylose is mostly due to the application of increasingly tight or furfuryl alcohol, a chemical that than commercial processes. Having converted, in an integrated way, to xylitol environmental regulations. is principally used to manufacture achieved this result, DLO scientists BIOREFINING AND PENTOSES (see below). Arabinose is classified as a resins for bonding foundry sands that are now studying how to best isolate rare sugar that is only produced in small Analysts predict that the xylitol market compose foundry molds. Currently furfural from the reaction medium. amounts, being used as a chemical for will undergo significant growth once suf- furfural is made directly from agri- Driven by the glucose to ethanol chal- specialty applications and as a food in- ficient quantities of industrial grade, cost cultural raw materials in a continuous Bioenergy Crop Plant Cells Xylitol lenge, the extraction and deconstruc- gredient in Japan. Regarding xylose, this competitive xylose (>98% pure) become process that employs sulphuric acid. Xylitol is a five-carbon tion of have been the focus sugar can be produced from black liquor, a available. Therefore, the main challenge is However, it is expected that advanced that is best known for its sweete- of much research over the last few byproduct of dissolving pulp manufacture. to lower the cost of xylose and arabinose biorefining will generate pentose-rich ning capacity, which exceeds that of decades. However, economically- A major European producer is Danisco extraction and purification. hydrolysates that will constitute new . As such, it is an excellent Plant Cell Wall important crops, such as cereals, raw materials for this industry. Today, artificial sweetener that is now used non-food crops and hardwoods, USES OF D-XYLOSE FOR THE MANUFACTURE about 90 percent of furfural produc- widely by the confectionary industry, also contain up to 30% dry weight of tion capacity is present in just three being responsible for the cold, fresh , which are mainly ara- OF INDUSTRIAL PRODUCTS countries, China, the biggest produ- sensation of certain chewing gums Cellulose binoxylans composed of D-xylose and cer, South Africa and the Dominican for example. Xylitol is also used for Microfibril Cellulose L-arabinose, or pentose sugars. Cur- C5 ethanol fine example is Clostridium acetobutylicum, Republic, with most furfural being caries prevention. However, xylitol Fig. 1 – Plant cell wall utilization of lignin, rent uses for these sugars are limited, hemicellulose and cellulose. © Elsevier - Several decades of research have been de- an anaerobic bacterium that for over half a converted into furfuryl alcohol. is also increasingly used in other partly due to the fact that high purity License Number: 3012501219608. voted to the development of microbial strains century formed the basis of the industrial industrial sectors, for example in D-xylose and L-arabinose are not yet S. cerevisiae that can produce ethanol using ABE (acetone-butanol-ethanol) process, In BIOCORE, scientists at DLO are pharmaceutical and cosmetic pro- produced as commodity chemicals. to breakdown the biomass into its D-xylose. The engineering strategies aim to which primarily manufactured acetone, pro- aiming to use furfural to prepare a ducts such as toothpaste, fluoride However, their future use as platform component parts, cellulose, drive D-xylose into the pentose phosphate ducing butanol and ethanol as co-products. biobased diisocyanate for the for- tablets and mouthwashes and has intermediates will be necessary in and pentose sugars from feedstocks, pathway (PPP) through its conversion into the This process was abandoned after 1945, mulation of polyurethanes, which been tested as a co-monomer with order to ensure the sustainability and such as wheat straw, birchwood or derivative, D-. Once phospho- only because of the availability of cheaper can be used in coating and foam terephthalatic or sebacic acid for economic viability of lignocellulosic poplar. The pentose sugars are rylated, D-xylulose-5-phosphate can enter acetone made from petroleum resources. applications. To achieve this, DLO polyester production. The current biomass value chains and to avoid obtained in an impure liquid stream the central of S. cerevisae via scientists submit the pentose-rich global demand for xylitol is approxi- excessive use of D-glucose. that also contains glucose, proteins, the pentose phosphate pathway. One way to In BIOCORE, INRA-affiliated researchers stream from the CIMV process to mately 160,000 tons per annum, a phenolic compounds, minerals and convert D-xylose into D-xylulose is to use a have been working on the engineering of a thermal conversion process in market that is undergoing a yearly Biorefining in BIOCORE acids from the extraction process. It D-. C. acetobutylicum to create a microorganism growth rate of about 5%. Most of the Xylitol In BIOCORE, CIMV S.A. (Levallois is this biorefinery stream that BIO- capable of producing isopropanol, one the OH OH current xylitol production is based in Perret, France) provides the biomass CORE researchers are using as a raw In BIOCORE, DSM has further developed the World’s most widely used industrial solvents HO OH China and the world price is situated fractionation technology, which uses material to imagine new technolo- xylose isomerase technology, generating a and a potential future precursor for the OH in the price range €5,000-6,000 per a mixture of formic and acetic acid gies and products. yeast that is capable of simultaneously production of propylene (via a dehydration Hydrogenation ton. Xylitol is currently manufactured

converting both C6 and C5 sugars to etha- step), a petroleum-derivative that is actually O in a 3-step process that involves the OH Oxidation nol. In this manner, ethanol production using currently used to manufacture isopropanol. Dehydration OH OH catalytic hydrogenation of D-xylose O hydrolysates of cellulose pulp supplied by In BIOCORE, researchers have engineered O OH HO O (or xylose-rich hydrolysates) using HO OH OH -1 CIMV could be boosted by at least 8% when a strain that can produce up 21 g L of the Furfural OH Xylonic acid a Raney nickel catalyst. Advanta- C5 sugars arising from the CIMV process IBE solvent mixture (i.e. replacing acetone Xylose geously, this catalyst is cheap and were added to the glucose-rich hydrolysate. by isopropanol) and work is currently unde- OH displays quite good activity and se-

rway to achieve the second aim, which is H C OH H C lectivity, but is nevertheless prone to 3 3 CH3 Isopropanol to produce isopropanol as a sole product, Ethanol Isopropanol fast deactivation, due to poisoning, Other industrial microorganisms also possess disrupting the metabolic steps that lead to and can result in nickel being pres- Fig. 2 – From left to right: cellulose, powder lignin, wheat straw, C5 syrup (hemicellulose) © Fig. 3 – Conversion of xylose into CIMV. the ability to consume pentose sugars. One the formation of butanol and ethanol. commercially-relevant products ent in the xylitol product.

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