Polyhydroxyalkanoates (PHA) production in bacterial co‐culture using glucose and volatile fatty acids as carbon source

Abstract

Mixed bacterial cultures are increasingly being used in the production of polyhydroxyalkanoates (PHAs), as they have the potential to be more cost effective than axenic pure cultures. The purpose of this study was to use pure cultures in combination to identify their potential of PHA production. In this work we used volatile fatty acids (VFAs) and glucose as carbon source to check the ability of selected strains ST2 (Pseudomonas sp.) and CS8 (Bacillus sp.) as co-culture. The production of PHA in pure co-cultures of bacteria was therefore investigated in order to understand the effect of combining cultures on PHA production parameters and material properties. Bacteria could use the feed in better way when mixed as compared to individual strain. In undertaking this analysis, model volatile fatty acids (i.e., acetic and propionic acids) were used alone and in combination with glucose as feedstock. The production by Pseudomonas was 34% while 24% by Bacillus. However when combined and mixed feed (glucose + propionic acid) was used, 35% PHA produced. Overall, it was found that the ability of the pure cultures to produce PHA was low but when selected cultures were mixed, their ability to produce PHA was enhanced. Copolymers were obtained instead of homopolymers with improved properties. This suggests that industrial wastewater rich in volatile fatty acids and carbohydrates can be a good carbon source for PHA production with variable properties.

Production of polyhydroxyalkanoates (PHAs) by Bacillus megaterium using food waste acidogenic fermentation-derived volatile fatty acids

“…Related advantages include high growth rate, absence of lipopolysaccharide layer which facilitates PHAs extraction, and the ability to produce hydrolytic enzymes that aid hydrolysis of more complex low-value substrates for subsequent use as carbon sources for PHAs production [24][25][26]. In fact, members of the genus Bacillus have been widely studied for PHAs production using synthetic media containing common carbon sources such as arabinose [27], glucose [27][28][29][30], glycerol [31,32], lactose [30,32], and sucrose [27,30,33]. Besides, VFAs including acetic acid [28,32], propionic acid [28], butyric acid [32], octanoic acid [32], among others, were also applied and at some extent, led to positive results.…”

“…In fact, members of the genus Bacillus have been widely studied for PHAs production using synthetic media containing common carbon sources such as arabinose [27], glucose [27][28][29][30], glycerol [31,32], lactose [30,32], and sucrose [27,30,33]. Besides, VFAs including acetic acid [28,32], propionic acid [28], butyric acid [32], octanoic acid [32], among others, were also applied and at some extent, led to positive results. However, the effect of VFAs type on PHAs production was in focus, while further studies are needed to evaluate the effect of using mixtures of VFAs on PHAs production using a wider range of strains and substrates used for acidogenic fermentation.…”

Electrospinning nanofibers of microbial polyhydroxyalkanoates for applications in medical tissue engineering

“…The wastes tested including municipal waste, 33,[49][50][51] sludge fermentation supernatant, 52 food production waste, 32,36,38,40,42,53,54 pulp waste, and various agricultural wastes. 44,56 However, despite the wide variety of possible feedstock, very few studies have dealt with toxic substances contained in industrial wastewaters for PHAs production. Zhang et al 57 used phenol as the carbon source for PHAs, and an alternative way of producing PHAs is to use of cyanobacteria.…”

Production Of Value-Added Products From Waste Derived Volatile Fatty Acids: A Review

“…As expected, there is a defined number of organisms within the MFC and the reactor can only handle a certain OLR in order to produce electricity at an optimum rate. (Bengtsson, et al, 2017) Glucose Batch, 30 o C, 2 Days, pH Uncontrolled 32% (Munir, et al, 2018) Glucose & Propionic Acid Batch, 30 o C, 2 Days, pH Uncontrolled 35% (Munir, et al, 2018) Fresh Cheese Whey CSTR, 25 o C, 4 Days, pH 8.8 659 gPHA/kgVSS (Colombo, et al, 2016) Sterilized Cheese Whey CSTR, 25 o C, 4 Days, pH 8.8 814 gPHA/kgVSS (Colombo, et al, 2016)…”