Improved fed-batch production of high-purity PHB (poly-3 hydroxy butyrate) by Cupriavidus necator (MTCC 1472) from sucrose-based cheap substrates under response surface-optimized conditions

Abstract

Experimental investigations were carried out for (MTCC 1472)-based improved production of poly-3 hydroxy butyrate (PHB) through induced nitrogen limiting fed-batch cultivation strategies. Initially Plackett-Burman design and response surface methodology were implemented to optimize most influencing process parameters. With optimized process parameter values, continuous feeding strategies ware applied in a 5-l fermenter with table sugar concentration of 100 g/l, nitrogen concentration of 0.12 g/l for fed-batch fermentation with varying dilution rates of 0.02 and 0.046 1/h. To get enriched production of PHB, concentration of the sugar was further increased to 150 and 200 g/l in feeding. Maximum concentrations of PHB achieved were 22.35 and 23.07 g/l at those dilution rates when sugar concentration maintains at 200 g/l in feeding. At maximum concentration of PHB (23.07 g/l), productivity of 0.58 g/l h was achieved with maximum PHB accumulation efficiency up to 64% of the dry weight of biomass. High purity of PHB, close to medical grade was achieved after surfactant hypochlorite extraction method, and it was further confirmed by SEM, EDX, and XRD studies.

Production of Polyhydroxybutyrate (PHB) and Factors Impacting Its Chemical and Mechanical Characteristics

“…Even though batch and fed batch processes are well known and established methods for PHB materials production, emerging fermentation processes are being further studied, with continuous feeding considered to be the simplest and the most ideal method for the PHB production when compared with other methods [59]. The continuous fermentation processes are recognized to operate under steady, controlled conditions, where factors that can affect the process such as the pH, nutrient supply, and concentration of the product are kept constant.…”

Emergent Approaches to Efficient and Sustainable Polyhydroxyalkanoate Production

“…Dey and Rangarajan reported a HCDC of C. necator (MTCC 1472) on sucrose for P3HB formation by a fed batch fermentation [ 63 ]. Under nitrogen limited fed-batch cultivation, the concentration during feeding of sucrose was varied from 100–200 g/L.…”

“…Under nitrogen limited fed-batch cultivation, the concentration during feeding of sucrose was varied from 100–200 g/L. The total biomass, %-P3HB in the CDW and overall productivity reached 38 g/L, 62% and 0.58 g/L/h, respectively, at a dilution rate of 0.046 h −1 and by feeding a 200 g/L sucrose solution [ 63 ]. The authors claimed their approach provided an economically attractive route to PHB production.…”

Obtención polihidroxialcanoatos (PHA) a partir de biomasa lignocelulósica: un estudio de revisión

“…Para la síntesis de PHB el microorganismo más utilizado es la bacteria Ralstonia eutropha, por su capacidad para almacenar hasta un 96 % del polímero en peso seco, utilizando fuentes de carbono provenientes de residuos agroindustriales. Esta bacteria, según la última clasificación taxonómica, se conoce también como Cupriavidus necátor (Dey;Rangarajan, 2017;Madeiros-Garcia et al, 2020). Investigaciones reportan que R. eutropha es capaz de metabolizar varios hidrolizados obtenidos a partir de fuentes lignocelulósicas, en cuya composición de azúcares se encuentran la glucosa y xilosa, principalmente (Ranganathan;Dutta;Moses;Anandharamakrishnan, 2020).…”

“…Una baja concentración de oxígeno disuelto promueve la síntesis de PHB; ya que se induce el metabolismo de consumo de azúcares de 5 carbonos. Por el contrario, valores altos promueven solo el crecimiento celular (Dey;Rangarajan, 2017).…”