Construction and analysis of a Pseudomonas‐Saccharomyces microbial consortium for mcl‐PHA production from xylose and octanoate

Abstract

Microbial consortia have great potential for the production of polyhydroxyalkanoates (PHAs) due to their comprehensive capability. In this study, a microbial consortium consisting of Pseudomonas putida NBRC14164 and Saccharomyces cerevisiae SyBE_Sc01020078 was constructed where xylose was converted into nutrients utilizable to P. putida by S. cerevisiae to realize the production of medium‐chain‐length polyhydroxyalkanoates (mcl‐PHAs) from xylose and octanoate, followed by a preliminary analysis of the interaction between the two strains. The optimal inoculation ratio consisted of 1% P. putida and 10% S. cerevisiae, and both strains exhibited the highest PHA production at their mid‐exponential phase. The two microorganisms were grown in a mineral salt medium with xylose and octanoate as substrates without washing and cultured at 200 rpm. The mcl‐PHA titre of this consortium was 295.7 mg/L, which was 150% higher than that of P. putida in pure culture. Metabolites analysis by gas chromatography–mass spectrometry revealed metabolic communication between P. putida and S. cerevisiae, whereby the former provided histidine, methionine, and leucine for the latter, while the latter converted xylose into lactic acid, which is a more accessible carbon source for the former.

Valorisation of Sugarcane Bagasse for the Sustainable Production of Polyhydroxyalkanoates

“…Therefore, the coculture approach is a potential alternative for the efficient bioconversion of lignocellulosic feedstocks into valuable biopolymers [49]. Studies on synthetic co-cultures have primarily focused on the use of a broader range of simple substrates, the neutralisation of toxic by-products and the synthesis of mcl-PHAs [49,144,[149][150][151]. However, research on the use of synthetic co-culture systems to produce PHA from complex substrates such as SCB is still at an early stage and needs more investigation in terms of exploring microbial interactions and bioprocess optimisation.…”

Perspectives in growth production trade-off in microbial bioproduction

“…Finally, instead of implementing GC with multiple substrates in the same strain, a viable near-future alternative is a one-pot synthetic microbial community of GC engineered strains for division of labor for bioconversion of specific substrates efficiently. Similar division of labor has been used to reduce metabolic burden in P. putida and S. cerevisiae consortium to produce 295.7 mg/L mcl-PHA titers 59 . Synthetic microbial consortium of P. putida and E. coli was recently reported where the has been utilized to substrate utilization and production was decoupled into the two strains that resulted in 1.32 g/L of mcl-PHA from 20 g/L of a glucose-xylose mixture (1:1) 60 .…”

“…A similar division of labor has been used to reduce the metabolic burden in a P. putida and S. cerevisiae consortium to produce 295.7 mg L −1 mcl-PHA titer. 59 Recently, a synthetic microbial consortium of P. putida and E. coli was reported, where substrate utilization and production were decoupled in the two strains, which resulted in 1.32 g L −1 of mcl-PHA from 20 g L −1 of a glucose–xylose mixture (1 : 1). 60 Computational dynamic modeling has also been used to study the trade-off between productivity and efficiency of substrate utilization in a synthetic consortium of E. coli strains, with one producing a heterologous protein together with a second E. coli strain engineered to scavenge acetate.…”