Loss of Serine-Type D-Ala-D-Ala Carboxypeptidase DacA Enhances Prodigiosin Production in Serratia marcescens

Abstract

Serratia marcescens, a gram-negative bacterium, found in a wide range of ecological niches can produce several high-value products, including prodigiosin, althiomycin, and serratamolide. Among them, prodigiosin has attracted attention due to its immunosuppressive, antimicrobial, and anticancer properties. However, the regulatory mechanisms behind prodigiosin synthesis in Serratia marcescens remains limited. Here, a transposon mutant library was constructed to identify the genes related to prodigiosin synthesis, and BVG90_02415 gene encoding a peptidoglycan synthesizing enzyme D-Ala-D-Ala carboxypeptidase DacA was found to negatively regulates prodigiosin synthesis. Quantitative measurements revealed that disruption of dacA increased prodigiosin production 1.46-fold that of the wild-type strain JNB5-1 in fermentation medium. By comparing differences in cell growth, pigA gene expression level, cell morphology, membrane permeability, and intracellular prodigiosin concentration between wild-type strain JNB5-1 and dacA mutant SK4-72, results revealed that the mechanism for hyper-producing of prodigiosin by the dacA mutant was probably that dacA disruption enhanced prodigiosin leakage, which in turn alleviated feedback inhibition of prodigiosin and increased expression of pig gene cluster. Collectively, this work provides a novel insight into regulatory mechanisms of prodigiosin synthesis and uncovers new roles of DacA protein in regulating cell growth, cell morphology, and membrane permeability in Serratia marcescens. Finally, this study offers a new strategy for improving production of high-value compounds in Serratia marcescens.

High‐level production of microbial prodigiosin: A review

“…There have been many reports on improving the prodigiosin production ability of host bacteria by deleting or disrupting negative regulatory genes (Table 4). Pan et al [121] enhanced the prodigiosin leakage by disrupting D‐Ala‐D‐Ala carboxypeptidase gene dacA of S. marcescens , thereby reducing the feedback inhibition of prodigiosin and increasing the expression of the Pig cluster. The prodigiosin production of S. marcescens JNB5‐1 increased by 3.89‐fold [121].…”

“…Pan et al [121] enhanced the prodigiosin leakage by disrupting D‐Ala‐D‐Ala carboxypeptidase gene dacA of S. marcescens , thereby reducing the feedback inhibition of prodigiosin and increasing the expression of the Pig cluster. The prodigiosin production of S. marcescens JNB5‐1 increased by 3.89‐fold [121]. In another study, Sun et al [122] disrupted the ompR family transcriptional regulator cpxR of S. marcescens JNB5‐1 and increased the transcription level of Pig cluster and prodigiosin precursor pathway related genes.…”

Identification of Essential Genes Associated With Prodigiosin Production in Serratia marcescens FZSF02

“…Prodigiosin has generated great interest in recent years due to its broad biological activities such as anticancer and antimicrobial properties (Bérdy, 2005). Research has mainly focused on three aspects: the optimization of the isolation and the production of prodigiosin-producing strains (Yip et al, 2019), the biological activity of prodigiosin (Li et al, 2018), and the synthesis and regulation mechanisms of prodigiosin in bacterial strains (Pan et al, 2019;Sun et al, 2020). The synthesis and regulation mechanism of prodigiosin are essential for its effective production and modification and the foundation for its further applications.…”

Biogenic colourants in the textile industry – a promising and sustainable alternative to synthetic dyes

“…Prodigiosin (31) was produced in an engineered Serratia marcescens with 35 mol% yield using carbon source sucrose (16 g•L -1 concentration in medium). 96 Recombinant Rhodotorula toruloides yielded blue-coloured indigoidine ( 42) with 14 mol% on glucose or 18 g•L -1 in medium. 97 Although some biotechnological processes show already decent yields, Table 2 indicates that other syntheses of biogenic dyes show rather low productivities.…”