Statistical physical and nutrient optimization of bioplastic polyhydroxybutyrate production by Cupriavidus necator

Abstract

Polyhydroxyalkanoates are biodegradable polymer materials that accumulate in numerous bacteria. The polyhydroxybutyrate is the most common type of polyhydroxyalkanoates, which potentially serves as precursor for bioplastic production. The most extensively studied polyhydroxybutyrate producing bacteria is Cupriavidus necator due to its capability to accumulate large amounts of this biopolymer in simple culture medium. Accumulation of polyhydroxyalkanoates granules in the cytoplasm of C. necator significantly depended on pH, aeration, carbon sources, nitrogen sources, and minerals in the culture medium. In the present study, the effect of both nutritional and physical variables on polyhydroxybutyrate production was investigated in order to optimize these conditions. At first, on the basis of one-factor-at-a-time experiments, fructose and ammonium chloride were found to be the most suitable sources of carbon and nitrogen for biopolymer production. Then the most significant factors affecting granules accumulation were recognized as fructose, agitation speed, KH 2 PO 4 , and initial pH using the Plackett-Burman and central composite design. ANOVA analysis showed significant interaction between fructose and agitation speed. After optimization of the medium, compositions for polyhydroxybutyrate production were determined as follows: fructose 35 g/L, KH 2 PO 4 1.75 g/L, MgSO 4 Á7H 2 O 1.2 g/L, citric acid 1.7 g/L, trace element 10 mL/L, initial pH = 7, and agitation speed 175 rpm. Under this optimal culture conditions, the maximum yield of PHB was 7.48 g/L. The present strategies included in this study could be used for PHB production by this bacterium. These results are the highest values of PHB ever obtained from batch culture of C. necator reported so far.

Enhancement of bioplastic polyhydroxybutyrate P(3HB) production from glucose by newly engineered strain Cupriavidus necator NSDG-GG using response surface methodology

“…1). This indicates that the optimized combination of carbon and nitrogen sources at pH 6.8 and 200 rpm significantly increased biomass compared to that found by Aramvash et al (2015). They measured a biomass of 1.37 g/L from C. necator ATCC 17699 with 20 g/L glucose and 2.0 g/L (NH 4 ) 2 SO 4 at pH 7.0 after 48 h. The results revealed that this new mutant strain (C. necator NSDG-GG) in the present study is capable of increasing bio-transforming of glucose into biomass.…”

Fermentative Production of Polyhydroxyalkanoates (PHAs) from Glycerol by Zobellella taiwanensis Azu-IN1

“…Inorganic chemicals such as ammonia, or ammonium salts are an important for maximizing biomass concentration and PHA accumulation [23]. Ammonium chloride was reported as the best nitrogen source for PHAs production by several researchers [17,[24][25][26]. Kalaiyezhini and Ramachandran [27] found that ammonium sulphate supported high growth and PHA production from glycerol in Paracoccus denitrificans.…”

Optimizing the biosynthesis of renewable polyhydroxyalkanoate copolymer containing 3-hydroxyvalerate by Massilia haematophila using statistical modeling

“…However, agitation rates below the optimal level caused cell aggregation and a heterogeneous culture media (Musa et al, 2016). Furthermore, agitation was used as an optimisation parameter of PHA production in several studies (Aramvash et al, 2015;Geethu et al, 2019). Increasing the concentration of 1-pentanol from 0.03 to 0.09 wt% considerably increased the 3HV monomer composition, but the latter was unaffected by agitation or incubation time (Fig.…”