The transition of Rhodobacter sphaeroides into a microbial cell factory

Abstract

Microbial cell factories are the workhorses of industrial biotechnology and improving their performances can significantly optimize industrial bioprocesses. Microbial strain engineering is often employed for increasing the competitiveness of bio‐based product synthesis over more classical petroleum‐based synthesis. Recently, efforts for strain optimization have been standardized within the iterative concept of “design‐build‐test‐learn” (DBTL). This approach has been successfully employed for the improvement of traditional cell factories like Escherichia coli and Saccharomyces cerevisiae. Within the past decade, several new‐to‐industry microorganisms have been investigated as novel cell factories, including the versatile α‐proteobacterium Rhodobacter sphaeroides. Despite its history as a laboratory strain for fundamental studies, there is a growing interest in this bacterium for its ability to synthesize relevant compounds for the bioeconomy, such as isoprenoids, poly‐β‐hydroxybutyrate, and hydrogen. In this study, we reflect on the reasons for establishing R. sphaeroides as a cell factory from the perspective of the DBTL concept. Moreover, we discuss current and future opportunities for extending the use of this microorganism for the bio‐based economy. We believe that applying the DBTL pipeline for R. sphaeroides will further strengthen its relevance as a microbial cell factory. Moreover, the proposed use of strain engineering via the DBTL approach may be extended to other microorganisms that have not been critically investigated yet for industrial applications.

High-Yielding Terpene-Based Biofuel Production in Rhodobacter capsulatus

“…Purple nonsulfur photosynthetic bacterium (PNSB) can capture light energy by the photosynthetic apparatus to drive the cyclic electron transport coupled with photophosphorylation to form ATP, and then the proton is reduced to H 2 mediated by nitrogenase. Photofermentation by PNSB is regarded as a feasible approach for biohydrogen production. , For instance, our group has demonstrated various strategies including screening dominant mutants, strain engineering, and optimizing the fermentation process in achieving enhanced H 2 production in PNSB. − At the same time, PNSB has been treated as a promising platform for terpenoid productions because of its robust and effective terpenoid metabolism. − Hence, utilization of PNSB as a platform microbe might lead to a consolidated process for direct synthesis of bisabolane from bisabolene and hydrogen.…”

Microbiome diversity, composition and assembly in a California citrus orchard

“…We measured a strong enrichment pattern for some taxa including the bacteria Actinoplanes, Burkholderia, Mucilaginibacter, Rhizobium, Rhodobacter, and fungi Glomus, and Rhizophagus. All five bacteria can promote plant growth by either fixing nitrogen, solubilizing phosphorus, producing phytohormone production, and increasing abiotic stress tolerance as well as and protect against pathogens by producing antimicrobial compounds or priming plant defense (Santi et al, 2013;Zhang et al, 2017;Orsi et al, 2021;Boukhatem et al, 2022;Fan and Smith, 2022). Glomus and Rhizophagus are arbuscular mycorrhizal fungi (AMF) that commonly form symbiotic associations with the plant host, including citrus.…”

Regulation of Reactive Oxygen Species Promotes Growth and Carotenoid Production Under Autotrophic Conditions in Rhodobacter sphaeroides

“…One of the chemolitotrophs, Rhodobacter sphaeroides , is attracting attention as an industrial cell factory producing biochemicals. It has a variety of useful metabolic pathways and can uptake CO 2 as well as sugar and organic acids via the Calvin-Benson-Bassham (CBB) pathway ( Orsi et al, 2021 ). In order to increase the productivity of PHB and biohydrogen, genetic modification, and optimization of environmental conditions including temperature, carbon source, and carbon/nitrogen ratio has been conducted ( Ghimire et al, 2015 ; Lee Y. R. et al, 2020 ).…”