Direct production of polyhydroxybutyrate and alginate from crude glycerol by Azotobacter vinelandii using atmospheric nitrogen

Abstract

While biodiesel is drawing attention as an eco-friendly fuel, the use of crude glycerol, a byproduct of the fuel production process, has increasingly become a concern to be addressed. Here we show the development of a low-cost fermentation technology using an atmospheric nitrogen-fixing bacterium to recycle crude glycerol into functional biopolymers. Azotobacter vinelandii showed substantial growth on tap water-diluted crude glycerol without any pretreatment. The number of viable A. vinelandii cells increased over 1000-fold under optimal growth conditions. Most of the glycerol content (~ 0.2%) in the crude glycerol medium was completely depleted within 48 h of culture. Useful polymers, such as polyhydroxybutyrate and alginate, were also produced. Polyhydroxybutyrate productivity was increased ten-fold by blocking the alginate synthesis pathway. Although there are few examples of using crude glycerol directly as a carbon source for microbial fermentation, there are no reports on the use of crude glycerol without the addition of a nitrogen source. This study demonstrated that it is possible to develop a technology to produce industrially useful polymers from crude glycerol through energy-saving and energy-efficient fermentation using the atmospheric nitrogen-fixing microorganism A. vinelandii.

High value-added fuel additive production from waste bio-glycerol over a versatile nanohybrid catalyst

“…2 Approximately 10% of crude glycerol is generated as a by-product during the transesterification reaction used in biodiesel synthesis. 3 The surplus production of glycerol disrupts the supply-demand balance, leading to a significant drop in its price. Consequently, there is growing interest in converting glycerol into high-value-added products due to its wide range of potential applications.…”

Production of biopolymer polyhydroxybutyrate from coconut coir hydrolysate: Characterization and optimization study

“…PHB was previously reported to be produced by several bacteria, including Cuprividus (Biglari et al, 2018), Azotobacter (Yoshida et al, 2022), andPseudomonas (Venkateshwar Reddy et al, 2017).…”

“…PHB was previously reported to be produced by several bacteria, including Cuprividus (Biglari et al., 2018), Azotobacter (Yoshida et al., 2022), and Pseudomonas (Venkateshwar Reddy et al., 2017). Three enzymes are involved in the PHB production pathway: β‐ketothiolase enzyme (phbA gene) converts two acetyl‐CoA molecules to acetoacetyl‐CoA.…”

The 3D Printability and Mechanical Properties of Polyhydroxybutyrate (PHB) as Additives in Urethane Dimethacrylate (UDMA) Blends Polymer for Medical Application

“…Polyhydroxyalkanoates (PHA) are those among biopolymers that can act as an alternative to the synthetic polymers derived from petrochemicals [ 1 ]. PHA are biopolymers that are naturally derived and accumulated by different families of microorganisms such as Azotobacter, Bacillus and Pseudomonas [ 2 , 3 , 4 ]. PHA are classified according to their basic structural chain length: short chain length (consists of 3–5 carbons), medium chain length (6–14 carbons) and lastly long chain length (consists of more than 15 carbons) [ 5 ].…”