Recovering PHA from mixed microbial biomass: Using non-ionic surfactants as a pretreatment step

authors	Colombo, B; Pereira, J; Martins, M; Torres-Acosta, MA; Dias, ACRV; Lemos, PC; Ventura, SPM; Eisele, G; Alekseeva, A; Adani, F; Serafim, LS
nationality	International
journal	SEPARATION AND PURIFICATION TECHNOLOGY
author keywords	Polyhydroxyalkanoates; Surfactants; Extraction; Mixed Microbial Biomass; Economic and Environmental Analysis
keywords	HALOGENATED BY-PRODUCTS; CLOUD POINT EXTRACTION; POLYHYDROXYALKANOATE PHA; DIMETHYL CARBONATE; CULTURES; IMPACT; POLY(3-HYDROXYBUTYRATE); CRYSTALLIZATION; SPECTROSCOPY; STRATEGIES
abstract	Polyhydroxyalkanoates (PHA) are biodegradable plastics of microbial origin, whose biodegradability and thermochemical properties make them greener alternatives to conventional plastics. Despite their high industrial potential, the PHA' high production costs still hinder their application. Mixed microbial biomass combined with agro-industrial wastes are being used to strategically reduce these costs. However, it is still necessary to optimize the downstream processing, where the extraction process amounts to 30-50% of the total costs. Conventional processes apply chlorinated solvents to recover PHA from microbial biomass but cannot be implemented industrially due to environmental regulations. Alternative solvents, with good results of purity and recovery yields, usually have a negative impact on the molecular weight of the final polymer. In this work, the addition of a pretreatment based on non-ionic surfactants (Tween (R) 20, Brij (R) L4, and Triton (TM) X-114) to extract PHA from mixed microbial biomass selected on fermented agro-industrial wastes was investigated. The best results were obtained with Tween (R) 20 allowing for an increase in 50% compared with the use of dimethylcarbonate without any pretreatment (from 38.4 +/- 0.8% to 53 +/- 2%) and very close to those obtained with chloroform (63%). The extracted polymer was analysed and characterized, revealing a PHA of high purity (> 90%) and low molecular weight loss (under 24%). Additionally, a material-focused economic and a carbon footprint analysis were performed and supported the selection of the method as one of the cheapest options and with the lowest carbon footprint.
publisher	ELSEVIER
issn	1383-5866
isbn	1873-3794
year published	2020
volume	253
digital object identifier (doi)	10.1016/j.seppur.2020.117521
web of science category	Engineering, Chemical
subject category	Engineering
unique article identifier	WOS:000571529200010