Production of (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer from coffee waste oil using engineered Ralstonia eutropha

Abstract

Polyhydroxyalkonate (PHA) is a type of polymer that has the potential to replace petro-based plastics. To make PHA production more economically feasible, there is a need to find a new carbon source and engineer microbes to produce a commercially valuable polymer. Coffee waste is an inexpensive raw material that contains fatty acids. It can act as a sustainable carbon source and seems quite promising with PHA production in Ralstonia eutropha, which is a well-known microbe for PHA accumulation, and has the potential to utilize fatty acids. In this study, to make poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(HB-co-HHx)), which has superior properties in terms of biodegradability, biocompatibility, and mechanical strength, engineered strain Ralstonia eutropha Re2133 overexpressing (R)-specific enoyl coenzyme-A hydratase (phaJ) and PHA synthetase (phaC2) with deletion of acetoacetyl Co-A reductases (phaB1, phaB2, and phaB3) was used to produce PHA from coffee waste oil. At a coffee oil concentration of 1.5%, and C/N ratio of 20, the R. eutropha Re2133 fermentation process results in 69% w/w of DCW PHA accumulation and consists of HB (78 mol%) and HHx (22 mol%). This shows the feasibility of using coffee waste oil for P(HB-co-HHx) production, as it is a low-cost fatty acid enriched waste material.

Biodegradation of Wasted Bioplastics in Natural and Industrial Environments: A Review

“…A feeding simulating fermented olive mill wastewater (OMWW) was used to extract PHA from mixed microbial cultures [66]. Other carbon sources used for synthesizing PHAs by microbes can include waste frying or cooking oil, coffee waste, crude glycerol, molasses, and wastewater [67][68][69][70]. Industrial and municipal wastewater sludge, agricultural, and food waste were used to produce PHB through SSF [71,72].…”

Opportunities for the Use of Brazilian Biomass to Produce Renewable Chemicals and Materials

“…These polysaccharides are widely used in the food industry, and by performing an alkaline hydrogen peroxide treatment, it is possible to obtain a renewable biopolymeric film [213] . In addition, vegetable oil can be removed from SGC using n ‐hexane and can then be transformed into polyhydroxyalkonates by the bacteria Ralstonia eutropha , as a potential bio‐based substitute for petrol‐based polymers [214] . Finally, it was possible to recover high yields (92 %) of phenolic compounds, such as chlorogenic acid from SGC, using 1,6‐hexanediol and choline (in a 7 : 1 ratio) in a deep eutectic solvent‐based process [215] …”

Prospects for the Use of Whey for Polyhydroxyalkanoate (PHA) Production

“…Thus, the use of waste materials as carbon sources for microbial-derived PHA production has been proposed in order to simultaneously reduce both PHA production and waste disposable costs (Choi and Lee, 1999; Kim, 2000; Koller et al, 2017; Nielsen et al, 2017). Several waste sources have been used to produce PHAs with relative success (Marshall et al, 2013; Nikodinovic-Runic et al, 2013; Anjum et al, 2016; Koller et al, 2017), including domestic wastewater (Carucci et al, 2001); food waste (Rhu et al, 2003); molasses (Albuquerque et al, 2007; Carvalho et al, 2014); olive oil mill effluents (Dionisi et al, 2005); palm oil mill effluents (Din et al, 2012); tomato cannery water (Liu et al, 2008); lignocellulosic biomass (Bhatia et al, 2019); coffee waste (Bhatia et al, 2018); starch (Bhatia et al, 2015); biodiesel industry waste (Kumar et al, 2014a; Sathiyanarayanan et al, 2017); used cooking oil (Ciesielski et al, 2015; Kourmentza et al, 2017); pea-shells (Patel et al, 2012; Kumar et al, 2014b); paper mill wastewater (Jiang et al, 2012); bio-oil from the fast-pyrolysis of chicken beds (Moita and Lemos, 2012); and cheese whey (Table 1).…”