Insight into metabolic pathways of the potential biofuel producer, Paenibacillus polymyxa ICGEB2008

Abstract

BackgroundPaenibacillus polymyxa is a facultative anaerobe known for production of hydrolytic enzymes and various important biofuel molecules. Despite its wide industrial use and the availability of its genome sequence, very little is known about metabolic pathways operative in the Paenibacillus system. Here, we report metabolic insights of an insect gut symbiont, Paenibacillus polymyxa ICGEB2008, and reveal pathways playing an important role in the production of 2,3-butanediol and ethanol.ResultWe developed a metabolic network model of P. polymyxa ICGEB2008 with 133 metabolites and 158 reactions. Flux balance analysis was employed to investigate the importance of redox balance in ICGEB2008. This led to the detection of the Bifid shunt, a pathway previously not described in Paenibacillus, which can uncouple the production of ATP from the generation of reducing equivalents. Using a combined experimental and modeling approach, we further studied pathways involved in 2,3-butanediol and ethanol production and also demonstrated the production of hydrogen by the organism. We could further show that the nitrogen source is critical for metabolite production by Paenibacillus, and correctly quantify the influence on the by-product metabolite profile of ICGEB2008. Both simulations and experiments showed that metabolic flux is diverted from ethanol to acetate production when an oxidized nitrogen source is utilized.ConclusionWe have created a predictive model of the central carbon metabolism of P. polymyxa ICGEB2008 and could show the presence of the Bifid shunt and explain its role in ICGEB2008. An in-depth study has been performed to understand the metabolic pathways involved in ethanol, 2,3-butanediol and hydrogen production, which can be utilized as a basis for further metabolic engineering efforts to improve the efficiency of biofuel production by this P. polymyxa strain.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-015-0338-4) contains supplementary material, which is available to authorized users.

Bioprocess Development for 2,3‐Butanediol Production by Paenibacillus Strains

“…The catabolism of glucose in P. polymyxa has been described using genome‐based metabolic modeling 31. Catabolism of hexose occurs via glycolysis using the Embden‐Meyerhof‐Parnas pathway.…”

“…Catabolism of hexose occurs via glycolysis using the Embden‐Meyerhof‐Parnas pathway. A bypass pathway named “Bifid shunt” has been found for the first time in P. polymyxa , which allows flexible regulation of redox and energy requirements depending on the metabolic state of the microorganism 31. In turn, catabolism of pentose occurs by the combination between the pentose‐phosphate pathway and glycolysis 32.…”

Efficient Bioelectrochemical Conversion of Industrial Wastewater by Specific Strain Isolation and Community Adaptation

“…Cellulose can serve as a substrate for Clostridia and can be converted into glucose via cellobiose (Demain et al, 2005). Cellobiose can also be metabolized by Paenibacillus polymyxa (Adlakha et al, 2015) and it could be assumed that the same might be true for the Paenibacillus isolate analyzed in this study. Most probably, glycolysis can be conducted by all four isolates.…”

“…By mixed acid fermentation, E. coli can generate a series of fermentation products, like acetate, CO 2 or H 2 . Acetate can also be produced by several other processes, for example the so-called bifid shunt of P. polymyxa , a glycolytic bypass described by Adlakha et al (2015) or the Wood-Ljungdahl pathway, which is carried out by Clostridium strains (Ragsdale and Pierce, 2008). The isolated Clostridia could also conduct butyric acid fermentation, which would lead to the production of CO 2 or H 2 .…”

Screening of alginate lyase-excreting microorganisms from the surface of brown algae

“…Among them, novel alginolytic activity in Paenibacillus , Leclercia and Planomicrobium has not been previously reported. Paenibacillus produces many kinds of extracellular enzymes such as cellulose, proteases, amylase and other polysaccharide-degrading enzymes, which can be used in a wide range of industrial fields (Adlakha et al 2015; Budi et al 2000; Das et al 2016; Dong et al 2016; Lan Pham et al 1998; Mathews et al 2016). However, production of alginate lyase by Paenibacillus has never been reported.…”