Enhanced polyhydroxyalkanoate (PHA) production from the organic fraction of municipal solid waste by using mixed microbial culture

Abstract

BackgroundIn Europe, almost 87.6 million tonnes of food waste are produced. Despite the high biological value of food waste, traditional management solutions do not consider it as a precious resource. Many studies have reported the use of food waste for the production of high added value molecules. Polyhydroxyalkanoates (PHAs) represent a class of interesting bio-polyesters accumulated by different bacterial cells, and has been proposed for production from the organic fraction of municipal solid waste (OFMSW). Nevertheless, until now, no attention has been paid to the entire biological process leading to the transformation of food waste to organic acids (OA) and then to PHA, getting high PHA yield per food waste unit. In particular, the acid-generating process needs to be optimized, maximizing OA production from OFMSW. To do so, a pilot-scale Anaerobic Percolation Biocell Reactor (100 L in volume) was used to produce an OA-rich percolate from OFMSW which was used subsequently to produce PHA.ResultsThe optimized acidogenic process resulted in an OA production of 151 g kg−1 from fresh OFMSW. The subsequent optimization of PHA production from OA gave a PHA production, on average, of 223 ± 28 g kg−1 total OA fed. Total mass balance indicated, for the best case studied, a PHA production per OFMSW weight unit of 33.22 ± 4.2 g kg−1 from fresh OFMSW, corresponding to 114.4 ± 14.5 g kg−1 of total solids from OFMSW. PHA composition revealed a hydroxybutyrate/hydroxyvalerate (%) ratio of 53/47 and Mw of 8∙105 kDa with a low polydispersity index, i.e. 1.4.ConclusionsThis work showed how by optimizing acidic fermentation it could be possible to get a large amount of OA from OFMSW to be then transformed into PHA. This step is important as it greatly affects the total final PHA yield. Data obtained in this work can be useful as the starting point for considering the economic feasibility of PHA production from OFMSW by using mixed culture.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-017-0888-8) contains supplementary material, which is available to authorized users.

Evaluation of organic fractions of municipal solid waste as renewable feedstock for succinic acid production

“…The carbohydrate content of OFMSW is 30-60% depending on the origin of the waste and the region among other factors. The OFMSW has been evaluated for the production of polyhydroxyalkanoates (PHAs), biogas and biohydrogen via mixed cultures [4][5][6] as well as the production of bio-based fuels and platform chemicals, such as bioethanol, lactic acid and succinic acid, via single strain fermentations [7][8][9].…”

Preparation and Characterization of Electrospun Food Biopackaging Films of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Derived From Fruit Pulp Biowaste

“…In this sense, the production of PHA by mixed crops from renewable resources is both economically and environmentally attractive. In particular, the use of food waste as the raw material for the PHA production is a more economical and sustainable industrial form within the frame of the Circular Economy (Colombo et al, 2017). For example, fermented cheese whey (CW), whose potential due to high contents in proteins and sugars is mostly not fully valorized at present, can be used as the feeding solution for PHA production (Colombo et al, 2016;Martínez-Abad et al, 2016;Domingos et al, 2018).…”

The effect of methane and odd-chain fatty acids on 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) synthesis by a Methylosinus-dominated mixed culture

“…To date, many methane-utilizing cultures capable of PHA production have been reported in literature (Pfluger et al 2011;Pieja et al 2011aPieja et al , b, 2012Stein et al 2011;Zuniga et al 2011;Belova et al 2013;Matsen et al 2013;Rostkowski et al 2013;Yang et al 2013;Myung et al 2015;Sundstrom and Criddle 2015;Criddle and Myung 2016;Myung et al 2016Myung et al , 2017. However, in order to make PHA production more competitive also in economic terms, open mixed microbial cultures can be offered as an alternative strategy for producing PHAs at lower costs (Broholm et al 1992;Beun et al 2002;Salehizadeh and Van Loosdrecht 2004;Dias et al 2006;Helm et al 2006Helm et al , 2008Albuquerque et al 2010;Arcos-Hernandez et al 2010;Colombo et al 2017;Luangthongkam et al 2019).…”