Production and productivity of 1,3-propanediol from glycerol by Klebsiella pneumoniae GLC29

Abstract

a b s t r a c tInterest in the development of the bioproduction of 1,3-propanediol, an important chemical intermediate with various industrial applications, has increased in recent years. Klebsiella pneumoniae is one of the most studied and efficient bacteria for 1,3-propanediol production from glycerol. A new isolate of K. pneumoniae was investigated using response surface methodology by central composite design for the production of 1,3-propanediol using glycerol. The effects of pH, temperature, stirrer speed, and glycerol concentration on the production and productivity of 1,3-propanediol were examined. Considering both production and productivity, the best conditions for glycerol conversion in 1,3-propanediol are: a pH range of 6.9-7.1, a temperature between 33 and 38.5 • C, a stirrer speed of 110-180 rpm, and a glycerol concentration of 39-49 g l −1 . Batch fermentation carried out at a pH of 7.0, a temperature of 35 • C, a stirrer speed of 150 rpm, and a glycerol concentration of 40 g l −1 produced 20.4 g 1,3-propanediol l −1 , with a maximum volumetric productivity of 2.92 g l −1 h −1 and a yield of 0.51 g g −1 . The main byproducts were acetic acid (approximately 7.0 g l −1 ) and formate (approximately 3.7 g l −1 ). The newly isolated K. pneumoniae GLC29 showed potential for the conversion of glycerol into 1,3-propanediol, with high production and productivity.

Experimental Design For 1,3-Propanediol Biosynthesis by K. Pneumoniae GLC29 Using Glycerol

“…Biodiesel Glycerol, although had a longer fermentation (12 h), produced 27.6 g/l of 1,3-propanediol out of 66 g/l of biodiesel glycerol. These are an increase of 4 g/l and 7.2 g/l respectively since the last optimization of this strain by Da Silva et al [2]. Table 5 and 6 show the obtained data, specific growth, glycerol consumption, yields and productivity for each batch, respectively.…”

“…The microorganism K. pneumoniae CLG29 was previously isolated by Da Silva et al [2], and kept at -86°C in 20% glycerol solution or lyophilized. Subcultures were performed regularly to maintain the viability of the cultures.…”

“…Evolutionary analysis were conducted in MEGA6 [26]. Based on the relationship with the consensus to the other Klebsiella pneumoniae strains and its relative species, the bacteria isolated by Da Silva [2] is a Klebsiella pneumoniae.…”

“…In this context, biofuels are an alternative to replace oil-based fuels, and the use of biomass for production a promising alternative, as its demand is growing rapidly [2]. Studies already show that the use of biomass for energy purposes has a increasing participation into the world energy matrix, and by the year 2050, the use of available biomass is expected to double worldwide [3].…”

“…The objective of this work was to optimize production of 1,3-propanediol media culture of a new strain of Klebsiella pneumoniae GLC29 isolated by Da Silva et al [2].…”