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.
keywords
HALOGENATED BY-PRODUCTS; CLOUD POINT EXTRACTION; POLYHYDROXYALKANOATE PHA; DIMETHYL CARBONATE; CULTURES; IMPACT; POLY(3-HYDROXYBUTYRATE); CRYSTALLIZATION; SPECTROSCOPY; STRATEGIES
subject category
Engineering
authors
Colombo, B; Pereira, J; Martins, M; Torres-Acosta, MA; Dias, ACRV; Lemos, PC; Ventura, SPM; Eisele, G; Alekseeva, A; Adani, F; Serafim, LS
our authors
Joana Sofia Marques Pereira
PhD Student
Luísa Seuanes Serafim
Assistant Professor
Margarida Martins
PhD Studentacknowledgements
This work was developed within the scope of the project CICECOAveiro Institute of Materials (UIDB/50011/2020 & UIDP/50011/2020), Associate Laboratory for Green Chemistry - LAQV (UIDB/50006/2020), and CESAM (UIDB/50017/2020 & UIDP/50017/2020) financed by national funds through the FCT/MCTES and when appropriate cofinanced by FEDER under the PT2020 Partnership Agreement. This work was also financed by Regione Lombardia, Italian Government and European Community-Programma Operativo Regionale 2014-2020, Obiettivo Investimenti in Favore della Crescita e dell'Occupazione Asse Prioritario I -Rafforzare la Ricerca, lo Sviluppo e l'Innovazione. Azione I.1.b.1.3-Sostegno alle attivita collaborative di R&S per lo sviluppo di nuove tecnologie sostenibili, di nuovi prodotti e Servizi. Project ID 141082: Renewable RAw materials valorization for INnovative BiOplastic production from urban Waste (RAINBOW). The authors are grateful for the financial support of the Portuguese Foundation for Science and Technology (FCT) through the project Multipurpose strategies for broadband agro-forest and fisheries byproducts valorisation: a step forward for a truly integrated biorefinery (PAC -Programa de atividades Conjuntas), SAICTPAC/0040/2015, and for the contracts SFRH/BD/130003/2017 of J. Pereira, SFRH/BD/122220/2016 of M. Martins, IF/01054/2014/CP1224/CT0005 of Paulo C. Lemos, and CEECIND/02174/2017 of Ana Dias. Mario A. TorresAcosta gratefully acknowledges the support of the CONACyT grant No. 485025.