Co-Production of Propanediol and 3- hydroxy propionic acid from glycerol using novel Klebsiella pneumonia isolate

Abstract

3-hydroxypropionic acid (3-HP) is an important platform chemical from which a wide range of industrially important chemical compounds can be derived. The microbial production of 3-HP got significant attraction in recent years despite of the numerous challenges it faces. Redox imbalance and supplementation of expensive coenzyme B12 are the major bottlenecks in its production economics. K. pneumoniae, a natural producer of vitamin B₁₂ is capable of converting glycerol to 1,3-propanediol (PDO) and 3-hydroxypropionic acid (3-HP) in a redox balanced manner. However, commercial applications are hampered by its poor growth characteristics and excessive lipopolysaccharide synthesis (LPS). To conquer these constraints, five potential B₁₂ synthesizing new isolates were screened from oil spills. The various levels of screening, SAV7 outperformed other 273 isolates. The highest production of PDO (69.2 mM) and 3HP (2.6 mM) in 12 hrs under microaerobic condition (100 rpm) with a cumulative yield of 0.69 mol/mol from glycerol was evidenced from SAV7. SAV7 also showed superior growth characteristics (3.16 OD₆₀₀ Vs 2.51 OD₆₀₀) than the control strain Kp 109. The 16S rRNA sequencing results confirmed that new strain as Klebsiella pneumonia (Kp SAV7). The lesser LPS content and better sedimentation behaviour and the ability to produce 3-HP and PDO simultaneously in the absence of vitamin B₁₂ implies that Kp SAV7 is a promising strain for industrial co-production of 3-HP and PDO.