Microbial Metabolites

    One of the research lines of the EQ-2 group is the development of fermentative processes for manufacturing metabolites to be employed in chemical, pharmaceutical or food industries. The target products considered include xylitol, astaxanthin, lactic acid, succinic acid acid and fumaric acid. Ongoing studies are focused on the last three products:

    A) Lactic acid

    Lactic acid exists in two isomeric forms (L or D), and can be obtained by chemical or biotechnological ways. The chemical method uses acetonitrile as a raw material, and leads to a mixture of isomers. The biotechnological way involves the fermentation of sugars (obtained from renewable materials) by bacteria or fungi, and (depending on the microorganism) may lead to the selective of a single isomer (L or D). Lactic acid finds a number of applications in the food industry (as acidulant, preservative, etc.), in the pharmaceutical industry (for skin treatment) and in the chemical industry (particularly as an intermediate in the manufacture of biodegradable polymers). The market of lactic acid is in continuous change and growth, and is being favourably affected by the growing interest in the production of polylactic acid, which is considered as a “green” alternative to petroleum derived polymers such as polyethylene or polypropylene. To reach this goal, new developments are necessary in various fields, including: i) utilization of cheap raw materials, ii) limitation of processing costs, iii) design of cost-effective processes for purification and recovery. The EQ-2 group is working of these three fields of improvement.

    B) Succinic acid
    Succinic acid (butanedioic acid), a dicarboxilic acid with molecular formula C4H6O4, is currently produced by chemical methods from petroleum-derived chemicals. Succinic acid is a precursor of important industrial chemical products as adipic acid, 1,4-butanediol, tetrahydrofuran, N-methyl pyrrolidinone and gamma-butyrolactone. The succinic acid market is expected to increase markedly owing to its suitability as a feedstock for manufacturing biodegradable bioplastics such as polybutylene succinate (PBS) or polyamides. Recent economic analyses confirmed that the biotechnological production of succinic acid from cheap and renewable raw materials can compete with the chemical way. The EQ-2 group is working on the development, optimization and evaluation of biotechnological processes for obtaining succinic acid from lignocellulosic materials.

    C) Fumaric acid
    Fumaric acid is an unsaturated dicarboxylic acid with a broad spectrum of applications, including the chemical, pharmaceutical, food and cosmetics industries. In the field of the “sustainable development”, fumaric acid stands out for its applications based on polymerization and esterification reactions. Owing to this, fumaric acid has been cited as one of the chemical products with greater potential for large-scale production from biomass. The EQ-2 group works on the development of hydrolysis-fermentation processes for fumaric acid manufacture based on the utilization of lignocellulosic feedstocks, which are expected to results in improved profitability and decreased environmental impact, in a way similar to the one foreseen for second-generation biofuels.
    The responsible scientist for studies on the production of microbial metabolites are Prof. Dr. Juan Carlos Parajó, Prof. Dr. José Luis Alonso and Dr. Remedios Yáñez.

    Within this topic, several R&D projects (funded by the Ministry of Science and Innovation of the Spanish Government, and by Xunta of Galicia) are ongoing, as well as R&D contracts with companies.