Organic Acids: Key Facilitators of the Bio-economy

by Lorenz Bauer (Lee-Enterprises Consulting/Biofuels Digest) Recent declines in oil prices and the failure of start-up biofuel processes to meet production cost targets have increased the interest in producing value added chemicals from biomass as coproducts. The vision is that these products can leverage the production of fuel by providing revenue to supplement the lower value fuel products. Replacing fossil fuel derived chemicals with renewables is itself a societal goal. Early in the biomass utilization effort, organic acids derived from sugars or cellulose decomposition were identified as attractive target molecules.

A marketsandmarkets.com study estimated the market for renewable derived organic acids will grow to 9.29 Billion USD by 2021. However, the long term market potential is much greater. Recent efforts have led to significant commercial advances. However, scaling renewable organic acids to a level where they significantly impact overall carbon use provides significant technical and non-technical opportunities and challenges.

Organic acids are of interest because there is an existing market for large quantities for use in foods, beverages and chemicals. Acetic acid, citric acid, formic acid, lactic acid, propionic acid, and fumaric acid are currently the highest volume products. A significant portion of acetic, lactic and itaconic acids are already produced from renewable sources. It is possible that renewable materials can entirely replace petroleum derived organic acids if costs could be lowered and integrated large scale processes developed.

Many major chemical companies are investing in smaller start-ups to develop commercial products. This is a long term strategic investment plan aimed at protecting their business as against a return to high oil prices and increased pressure from governments and environmental motivated consumers.

Significant advances in technology are needed to make renewable organic acids and derived products cost competitive with their petroleum analogs.

The ability to produce higher concentrations of a specific product addresses one of the major limitations of the renewable production, product separation, and purification. Many of the applications require high purity materials. The cost of separation and purification can be 2/3 of the overall production costs of the acids.

As long as refined sugars are the major source of carbon it will be difficult to lower costs. There are also concerns of the sustainability of renewable sugars derived from sources currently used for food. Logistics are also a major issue including both transportation and dealing with seasonal supply variations. Continued progress towards economical production of fermentation feeds from lignocellulose could help alleviate this conflict. However, the impurities in the cellulose derived from this approach may limit the use of some promising strains of microbes.

Public perceptions of genetic modification and biotechnology needs to be improved. The products derived from these processes need to be accepted as natural and green.