By Jan H. Schut
Whatever happened to bio-based poly(butylene succinate)? Bio PBS, based on two new bio monomers, was supposed to be fully commercial by now. PBS is a low molecular weight, biodegradable polyester, which decomposes completely into CO2 and water and is often compared to LDPE or PP. It’s already made commercially from 50/50 petro-based succinic acid and 1,4 butanediol, but the petro route is expensive, so growth is limited.
The bio version is off to a slow start because no one so far has built large scale fermenters for the bio monomers. Five production partnerships were set up 6-8 years ago to ferment bio succinic acid and/or bio BDO, but so far they have built only semi-works plants. Three operate fermenters with combined capacity of only 74 million lb/year of bio succinic acid. A fourth fermenter starts next year with capacity for another 60 million lb/year of bio succinic acid, the biggest so far. A fifth company has technology to ferment bio BDO directly and has licensed it to two large chemical companies, which have done full-scale trials, but neither is in production. Bio BDO can also be made by purifying bio succinic acid.
Several Japanese and Korean companies have made small amounts of petro PBS for years. Showa Denko K.K., Tokyo (www.sdk.co.jp), commercialized Bionolle in the 1990s, developing automotive compounds. Mitsubishi Chemical Corp., Tokyo (www.mitsubishichem-hd.co.jp), introduced GS Pla in 2003 for biodegradable agricultural sheet and film and automotive compounds. IRe Chemical Ltd., Seoul (www.irechem.en.ec21.com), makes EnPol for biodegradable fish nets; and SK Chemicals Co. Ltd., Gyeonggi-do (wwwskchemicals.com), makes Skygreen.
The big PBS capacity, however, is Chinese–reportedly over 200 million lb/year. It is mostly swing plants, which can produce either PBS or PBAT, built with Chinese government grants targeting export of biodegradables to the U.S. and Europe. Kingfa Science & Technology Co., Zhuhai, Guangdong (www.kingfa.net), reportedly has capacity for 68 million lb/year of petro PBS; China New Materials Holdings Ltd., Zibo City, Shandong (www.sdfuwin.com) 55 million lb/year; XinFu Pharmaceutical Co. Ltd., Hangzhou, Zhejiang (www.xinfuchina.com) 28 million lb/year; and He Xing Chemical Co. Ltd., Anqing, Anhui (www.hexinggroup.com) 11 million lb/year. A fifth, Qixiang Tengda Chemical Co. Ltd. in Zibo, Shandong (www.qxgm.com), is reportedly building a whopping 330 million lb/year petro PBS plant to start in 2015, vertically integrated with succinic acid and BDO.
All that petro PBS capacity–potentially nearly 600 million lb/year—is important because it could convert quickly to bio succinic acid once bio is available, since it should cost less. (It supposedly takes 50% less energy to make bio succinic acid than petro.) A few small bio PBS reactors are also being built. PTTMCC Biochem Co. Ltd., a joint venture between PTT PLC Ltd., Bangkok, Thailand (www.pttplc.com) and Mitsubishi, is building a 44 million lb/year bio PBS reactor in Rayong, Thailand, to start in 2Q 2015. Youth Chemical, a unit of Jiangsu Yangnong Chemical Group Co. Ltd., Yangzhou, Jiangsu (www.yangnong.com.cn), started a 22 million lb/year pilot reactor for bio PBS in 2013. So there’s plenty of demand for bio succinic acid just for PBS. (Succinic acid is also used in paints, polyurethanes, and cosmetics.)
So why are the bio monomers lagging? One theory is that the semi-works succinic acid fermentation plants are trying to improve quality before scaling up, aimed at U.S. food contact approval for PBS, which it doesn’t now have. Mitsubishi says its GS Pla qualifies for food contact in Japan and Europe, but not yet in North America. Mitsubishi plans to apply for U.S. food contact approval for products from the Thai plant once it starts up. Single use cutlery and cup lids, common PBS applications, don’t need food contact approval.
There are two potential issues. PBS’s low molecular weight can be raised by reactive chain extension with potential for residues. Showa Denko, for example, uses diisocyanurate for chain extension. There is also low-level sniping among succinic acid producers over yeast vs. bacterial (E. coli) fermentation. The yeast route reportedly requires less cleaning of fermentation equipment to prevent infection and claims higher purity succinic acid. Yeast also produces succinic acid directly, while the bacterial route takes an extra step to convert succinic salt to acid.
Another issue may be the cost of bio BDO. There are also competing routes to bio BDO–direct bacterial fermentation vs. hydrogenation of bio succinic acid into BDO. Direct fermentation loses 50% of feedstock carbon as waste CO2. Refining bio succinic acid into bio BDO loses 15% of feedstock weight as water and adds the cost of conversion. So opinions vary on which will cost less and whether they will be cost competitive against petro BDO.
UPDATE ON BIO SUCCINIC ACID AND BIO BDO
Here’s a snapshot of the snail’s race. BioAmber Inc., Minneapolis, Minn. (www.bio-amber.com), has run a 6 million lb/year pilot fermenter in Pomacle, France, for four years and is building a 60 million lb/year semi-works fermenter in Sarnia, Ont., in a j/v with Mitsui & Co. (www.mitsui.com) to start in Q2 2015. BioAmber used bacterial fermentation of wheat glucose in France, but will use second generation yeast licensed from Cargill Inc., Minneapolis, Minn. (www.cargill.com), with corn glucose in Sarnia. BioAmber also plans to build two full-scale fermenters, one for 200 million lb/year of bio BDO to start in late 2017 with expansion for 140 million lb/year of bio succinic acid, and another for 400 million lb/year of bio succinic acid to start in 2020. BioAmber licenses catalyst technology from DuPont Co., Wilmington, Dela. (www.dupont.com) to hydrogenate bio succinic acid into BDO with 85% yield. Exporter Vinmar International Ltd., Houston, Texas (www.vinmar.com) will distribute output from all three plants. BioAmber originally planned to build a large bio succinic acid plant in Thailand with PTTMCC to supply PTTMCC’s bio PBS plant, but PTTMCC will now be supplied from Sarnia where energy and feedstock costs are lower. Bio Amber originally said its bio succinic acid would be competitive with petro succinic acid from $45/barrel oil, but lately says it will be cost equal if oil is at $35/barrel.
Myriant Corp., Quincy, Mass. (www.myriant.com), started a 30 million lb/year semi-works fermenter for bio succinic acid in Lake Providence, La., in 2013 using corn glucose as feedstock and bacterial fermentation licensed from the University of Florida, Gainesville (www.ufl.edu). Myriant’s process was developed by ThyssenKrupp Uhde GmbH (www.thyssenkrupp.com) at a pilot plant in Leuna, Germany. Myriant also partnered with Johnson Matthey Davy Technologies Ltd., London, U.K. (www.davyprotech.com), to be sure its bio succinic acid drops into Davy’s single-reactor BDO process to make bio BDO. PTT Global Chemical PLC Ltd. in Thailand (www.pttgcgroup.com), originally 50% owner of Myriant, increased its stake to 86%. Myriant plans to build a second bio succinic acid plant in Louisiana for 140 million lb/year by 2015. Myriant also previously planned two plants in Asia, one with PTT for biosuccinic acid, and another with China National BlueStar Co. Ltd., Beijing, China (www.china-bluestar.com) for Davy process bio BDO.
Succinity GmbH, Dusseldorf, Germany (www.succinity.com), a joint venture of Corbion Purac Biochem BV, Gorinchem, the Netherlands (www.corbion.com), and BASF SE, Ludwigshafen, Germany (www.basf.com), upgraded a 22 million lb/year lactic acid fermenter in Purac’s site in Montmelo, Spain, to make bio succinic acid. The Spanish plant started up in March 2014 using proprietary BASF bacteria. Succinity originally planned a 55 million lb/year succinic acid fermenter in Spain by 2013, but has since announced plans for a 110 million lb/year bio succinic acid fermenter, but hasn’t given a date or site.
Reverdia VOF in Geleen, the Netherlands (www.reverdia.com), a joint venture of Roquette Freres Group, a French starch producer, and Royal DSM NV, Heerlen, the Netherlands (www.dsm.com), started a demo fermenter for bio succinic acid in Lestrem, France, in 2010 (since closed) and a 22 million lb/year semi-works fermenter in Cassano Spinola, Italy, in 2010. Reverdia uses yeast-based fermentation with starch as feedstock and plans a second 100 million lb/year fermenter by 2016, but hasn’t determined the site.
Genomatica Inc., San Diego, Calif. (www.genomatica.com), has bacterial fermentation to make bio BDO directly and has licensed it to Novamont S.p.A., Novara, Italy (www.novamont.com), and BASF. Novamont is expected to convert a 40 millon lb/year plant in Adria, Italy, to Genomatica’s BDO process this year. BASF used the process for several commercial runs since 2013 and plans to build a 110 million lb/year Genomatica bio BDO plant, “depending on market acceptance,” BASF says. BASF and DSM both make PBT, which could potentially use bio BDO for partial bio content.
So in the next 5-6 years bio, or partially bio, PBS could finally become commercial. That’s a time line of 15-20 years, twice as long as Cargill’s NatureWorks took to launch its PLA biopolymer, which also needed a new bio monomer. PLA wasn’t a drop in polymer for an existing petro plastic like PBS, and there were few alternative suppliers, which made creating a market for PLA a lot more difficult. But NatureWorks lost no time on a semi-works plant. Instead Cargill went straight from a 9 million lb/year pilot fermenter for lactide monomer in 1996 to NatureWorks’ 300 million lb/year PLA plant by 2003, vertically integrating lactic acid, lactide monomer, and PLA. No guts, no glory.