Building a bio-economy from waste: making lactic acid from waste biomass

A stipend of £15,000 per annum is offered to a strong candidate for this full-time PhD studentship in the School of Science and Engineering at Teesside University.

The project aim is to use industrial waste feedstock to produce ethyl lactate (EL), an environmentally benign biosolvent. This will then be exploited as a substrate to produce racemic lactic acid (rac-LA) for subsequent manufacture of thermally stable, industrially robust and commercially competitive polylactic acid (PLA)-based bioplastics. This is central to the manufacturing of robust thermally stable PLA-based bioplastics with real competitive potential against non-sustainable alternatives such as PET. Despite this potential, the PLA’s industrial growth is limited by two key factors: feedstock and thermal stability. Also, PLA manufactured from L-LA has significant limitations in applications over 60 ⁰C due to its largely amorphous structure and crystallinity. Physical blending of L- and D-PLA polymers produces highly regular stereo-complex materials with significantly increased crystallinity and thermal stability. Thus expansion and development of current and new knowledge on how lactic acid bacteria generate rac-LA, and the optimum growth/process conditions, should result in a more streamlined pathway for PLA-derived bioplastics with potential to be more cost-effective and thermally stable. The objectives of the project are as follows: • To address the commercial potential of EL as an emerging ‘green solvent’. • To investigate the microbiological pathways that produce a racemic mixture of D- and L-lactic acid (rac-LA). • To investigate sources of waste biomass as a renewable substrate for commercially and sustainably competitive PLA-based bioplastics.