Green Chemistry, the Rebirth of Bio n-Butanol

John Warren,
Director, Government Affairs, Green Biologics
The growing popularity of 'Green' consumer goods is driving manufacturers to take another look at their basic product inputs and sources. Chemical formulations that serve as the building blocks for finished goods are sourced almost exclusively from the petro-chemical industry. But it was not always that way. With a commercial scale project underway, Green Biologics makes the technology leap and reintroduces the sugar pathway.

Through a combination of micro-organism development and process engineering improvement, Green Biologics Ltd (GBL) has been able to re-open the door to a long-practiced process for n-butanol production.

The Clostridia Acetone-Butanol-Ethanol(ABE) process was developed in Britain in the early part of the 20th century by Chaim Weizmann and became a well -understood and reliable process. Prior to the US petrochemical industry boom beginning in the 1940's, n-butanol was sourced through sugar fermentation pathways, primarily molasses. Economics drove the industry to shift to petrochemical sources, which has prevailed within the industry for nearly 75 years. Until recently, attempts at improving industrial fermentation economics including the technology needed for commercial scale competitiveness have been elusive, but GBL has solved the scale-up challenge . Through transformational biology and innovative fermentation advancements coupled with solvent recovery processes that elevate yields and conversion ratios to cost competitive levels, GBL stands on the verge of transition from a biotechnology development firm into a green chemical manufacturer. With the December 2014 purchase of an operational fuel ethanol plant in Minnesota (MN), USA, GBL is embarking on the final phase of commercial scale -up. The project to repurpose the facility with GBL’s advanced fermentation and advanced solvent recovery ABE platform is well underway and scheduled for completion in 2016.

GBL has experienced success at every level on the way to commercially viable performance. At their UK labs, GBL has developed strains specifically engineered for superior ABE performance, providing sustained highlevel productivity and enabling technology scale-up. GBL's strains can handle a broad range of substrates including C5 sugars, with the ABE clostridia micro -organisms representing just a sample of GBL’s library of over 400 solventogenic microbial biocatalysts. GBL has developed a broad portfolio of wholly-owned, product distinct property rights, consisting of know-how, patents, patentable technology, and biological assets focused on the strain development and advanced fermentation process configurations needed to make scale-up possible and profitable.

A key GBL process development enables high productivity (grams per litre hour) over extended fermentation cycles. Strain robustness allows typical batch cycle times to be extended by orders of magnitude. A combination of strain improvement, media optimisation and improved process control result in 3X productivity over typical batch processes. (See Figure 1)

For scale-up validation, GBL first tested the performance of their micro -organisms in commercial scale fermentation trials in China. Trials included the fermentation of C5 sugars derived from corn waste and demonstrated strain stability at commercial scale. At their pilot plant in Ohio, USA, GBL conducted approximately 77 pilot runs to develop the advanced fermentation process while developing operating conditions to maximise the ABE productivity. This pilot process scale is 150 litres. For demonstration scale validation, GBL invested in facilities in Iowa, USA that facilitated extensive process trials at a 40,000 litre fermentation scale, a significant milestone on the way to commercial scale of 1M litre fermenters. The completed trials included a series of metric batches to validate process viability, scalability, and effectiveness at achieving target production rates. Process conditions were analysed, optimised, and proven to replicate the output at the pilot scale. Key productivity parameters for the advanced fermentation process were '%' conversion, '%' n-butanol, and hours of operation. The sugar uptake and productivity results were at the target level and provide commercial scale confidence.

Commercial Scale Market Entry:
De-risking Plant 1
Plant 1, a repurpose of an ethanol plant in Minnesota represents GBL’s commercial launch. Project strategy and priority was to focus site selection on the distressed US ethanol industry. Supply and demand factors are driving the need for structural change in the ethanol industry, leaving a select number of small to midsize corn-based plants attractive targets for a conversion project. GBL is planning for Plant 2 and beyond call for cellulosic and waste derived feedstocks. But for Plant 1, starting with an existing plant and reliable corn sugar supply removed the feedstock risk, a major challenge in raising capital, deploying technology enhancements, and gaining market entry. By targeting existing US ethanol production, site options included ethanol plants that were not only attractive buy opportunities, but that offered similar process design and assets to those required for n-butanol. In carefully selecting the MN, USA location, GBL eliminated a number of risks common to commercial scale-up. In addition to feedstock supply and reduced capital exposure through repurpose of a distressed asset, the project inherited access to a skilled workforce, an established network of service providers and vendors, and ample utility infrastructure.

Moving Forward
With commercial market entry strategies in motion, GBL is turning focus to the long term commercial strategy of deploying projects that use alternative (non-grain) bio-based and industrial derived sugars. Organic feedstocks and advancements in pre-treatment processes will soon offer lowcost sugar options, opening the door to a wider range of inputs. GBL has worked with a wide range of lignocellulosic feedstocks, including agricultural wastes such as bagasse, corn stover and woody biomass, as well as organic municipal solid waste(MSW). Bench scale results have generated encouraging and commercially viable yields for both total solvent and butanol:solvent yields . Competing best-practice processes deliver butanol:solvent ratios of 0.6 (60%). GBL biocatalysts have demonstrated butanol:solvent ratios of 0.75 at pilot and demonstration scale, and 0.83 and higher at laboratory scale.

Both n-butanol and acetone are currently petroleum-based, commodity chemicals produced by large global players in the chemicals market including Dow, BASF, Eastman, and Oxea. However, there are no major producers currently manufacturing n-butanol on a commercial scale via a bio-based process. While there are several smaller bioproducts companies showing interest that have developed processes at pilot and demonstration scale, there are no companies who appear to be as far along in their commercialisation efforts as GBL. Through deployment of the MN, USA project, GBL appears poised to capture a leading position in the renewables chemical industry.

GBL is marketing their products as renewable chemicals that can be used as ingredients in a diverse range of green consumer goods. GBL is engaging a select list of companies involved in the upstream products used in the manufacture of consumer goods that can gain advantage through the use of biobased inputs. GBL is providing campaign trial material for customer trials in cosmetics, food ingredients, industrial cleaners, and paints. GBL products will ultimately be used in green versions of these consumer goods. The GBL Marketing Strategy Quick List includes: architectural paints, inks and toners, household cleaners, adhesives and sealants, charcoal lighting fluids, cosmetics, food ingredients/flavours, plasticisers, lubricants and additives.

Global Strategy
An advantage of the GBL technology is the ability to be replicated in a broad range of applications. The technology can be developed stand-alone, but GBL envisions production plants that leverage existing assets and feedstocks (eg, ethanol, sugar, pulp mills, bagasse, MSW). Employing a capital-efficient, margin-diverse operating model with a focus on low-cost, sustainable non-food feedstocks will allow GBL to build momentum and expand into international markets. With a history of success in China, and offices in the UK, US, India, and Brazil, GBL seeks global deployment opportunities that provide fast track routes to the manufacture of green chemicals.