Prodigiosin Production Research Articles

Ambigols from the Cyanobacterium Fischerella ambigua Increase Prodigiosin Production in Serratia spp.

When a library of 573 cyanobacteria extracts was screened for inhibition of the quorum sensing regulated prodigiosin production of Serratia marcescens, an extract of the cyanobacterium Fischerella ambigua (Näg.) Gomont 108b was found to drastically increase prodigiosin production. Bioactivity-guided isolation of the active compounds resulted in the two new natural products ambigol D and E along with the known ambigols A and C. Ambigol C treatment increased prodiginine production of Serratia sp. ATCC 39006 (S39006) by a factor of 10, while ambigols A and D were found to have antibiotic activity against this strain. The RNA-Seq of S39006 treated with ambigol C and subsequent differential gene expression and functional enrichment analyses indicated a significant downregulation of genes associated with the translation machinery and fatty acid biosynthesis in Serratia, as well as increased expression of genes related to the uptake of l-proline. These results suggest that the ambigols increase prodiginine production in S39006 not by activating the SmaIR quorum sensing system but possibly by increasing the precursor supply of l-proline and malonyl-CoA.

Antibiofilm and Antivirulence Properties of Indoles Against Serratia marcescens.

Indole and its derivatives have been shown to interfere with the quorum sensing (QS) systems of a wide range of bacterial pathogens. While indole has been previously shown to inhibit QS in Serratia marcescens, the effects of various indole derivatives on QS, biofilm formation, and virulence of S. marcescens remain unexplored. Hence, in the present study, we investigated the effects of 51 indole derivatives on S. marcescens biofilm formation, QS, and virulence factor production. The results obtained revealed that several indole derivatives (3-indoleacetonitrile, 5-fluoroindole, 6-fluoroindole, 7-fluoroindole, 7-methylindole, 7-nitroindole, 5-iodoindole, 5-fluoro-2-methylindole, 2-methylindole-3-carboxaldehyde, and 5-methylindole) dose-dependently interfered with quorum sensing (QS) and suppressed prodigiosin production, biofilm formation, swimming motility, and swarming motility. Further assays showed 6-fluoroindole and 7-methylindole suppressed fimbria-mediated yeast agglutination, extracellular polymeric substance production, and secretions of virulence factors (e.g., proteases and lipases). QS assays on Chromobacterium violaceum CV026 confirmed that indole derivatives interfered with QS. The current results demonstrate the antibiofilm and antivirulence properties of indole derivatives and their potentials in applications targeting S. marcescens virulence.

Utilization of Crab Waste for Cost-Effective Bioproduction of Prodigiosin.

This study aimed to establish the culture process for the cost-effective production of prodigiosin (PG) from demineralized crab shell powder (de-CSP), a fishery processing byproduct created via fermentation. Among the tested PG-producing strains, Serratia marcescens TNU02 was demonstrated to be the most active strain. Various ratios of protein/de-CSP were used as the sources of C/N for PG biosynthesis. The PG yield was significantly enhanced when the casein/de-CSP ratio was controlled in the range of 3/7 to 4/6. TNU02 produced PG with a high yield (5100 mg/L) in a 15 L bioreactor system containing 4.5 L of a newly-designed liquid medium containing 1.6% C/N source (protein/de-CSP ratio of 3/7), 0.02% (NH4)2SO4, 0.1% K2HPO4, and an initial pH of 6.15, at 27 °C for 8 h in dark conditions. The red pigment was purified from the culture broth and then quantified as being PG by specific Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) and UV spectra analysis. The purified PG demonstrated moderate antioxidant and effective inhibition against four cancerous cell lines. Notably, this study was the first to report on using crab wastes for PG bioproduction with high-level productivity (5100 mg/L) in a large scale (4.5 L per pilot) in a short period of fermentation time (8 h). The salt compositions, including (NH4)2SO4 and K2HPO4, were also a novel finding for the enhancement of PG yield by S. marcescens in this report.

Sotolon is a natural virulence mitigating agent in Serratia marcescens.

Serratia marcescens is an emerging opportunistic bacterium that can cause healthcare-associated infections. The high rate of multidrug resistance and the ability to produce a set of virulence factors, by which it can produce infectious diseases makes it urgent to find an alternative approach to the treatment of such infections. Disarming of virulence by targeting of quorum sensing (QS) as the regulating mechanism of virulence is a promising approach that has no effect on bacterial growth that is considered a key factor in emergence of resistance. This study was designed to investigate the ability of sub-inhibitory concentrations (sub-MICs) of sotolon to attenuate virulence of a clinical isolate of S. marcescens. Sotolon at 25 and 50μg/ml inhibited 35.2 and 47.5% of biofilm formation, respectively. The inhibition of swimming motility were 41.4 and 69.3%, while that of swarming motility were 77.6 and 86.8% at 25 and 50µg/ml, respectively. Moreover, sotolon reduced prodigiosin production by 76.6 and 87.6% at concentrations of 25 and 50µg/ml, respectively. Protease activity was reduced by 25µg/ml of sotolon by 54.8% and was completely blocked at 50µg/ml. The relative expression of genes regulating virulence factors decreased by 40% forfimA, 29% for fimC, 59% for flhC, 57% for flhD, 39% for bsmB, 37% for rssB, 49% for rsmA, 54% for pigP, and62% for shlA gene in the presence of 50µg/ml sotolon. In conclusion, sotolon is an anti-virulence agent that could be used for the treatment of S.marcescens hospital-acquired infections.

Biotransformation of paper mill sludge by Serratia marcescens NITDPER1 for prodigiosin and cellulose nanocrystals: A strategic valorization approach

Paper mill sludge (PMS), a lignocellulosic waste from paper industry, is an ecological burden of environmental concern. Present study explored PMS as substrate for prodigiosin production in solid state fermentation (SSF) and concurrent source of cellulose for Cellulose nanocrystals (CNCs) preparation, using Serratia marcescens NITDPER1. Batch studies revealed maximum pigment production 47 ± 3.2 mg/L after 60 h and ligninolytic potentials via kraft lignin degradation (59 % after 72 h), lignin-mimicking dye decolourization and lignin monomer utilization. In SSF, highest yield was 30.05 ± 1.7 mg/g (24 h) with growth-associated (α = 20.84) and non-growth associated (β = 0.63) parameters determined through Luedeking-Piret model. Lambda max (535 nm), Thin-Layer Chromatography (TLC) (Rf = 0.9), High-Performance Liquid Chromatography (HPLC) (RT = 2.865), Fourier-transform infrared spectra (FT-IR) and Nuclear magnetic resonance (NMR) confirmed it as prodigiosin that exhibited antioxidant potential (IC50 = 47 ± 3.5 μg/mL). After SSF, the delignified (54 %) residual PMS was utilized for preparing CNCs, that displayed particle size 130.8 nm, zeta potential -13.4 mv, polydispersity index 0.404, stability upto 490 °C and revealed desirable properties in Field-emission scanning electron microscopy (FESEM), FT-IR and X-ray diffraction (XRD). Phytotoxicity studies confirmed both prodigiosin and CNCs as non-toxic. This study unveiled biorefinery perspectives for paper industries through production of two commercially important commodities from waste using eco-friendly approach.

A comprehensive review on recent trends in production, purification, and applications of prodigiosin

Increasing utilization of artificial chemical dyes as coloring agent and their associated detrimental effects on human health have instigated the search for novel natural pigments for applications in the food and pharmaceutical industries. A wide range of advancements have been recorded for utilization of naturally extracted pigments, owing to their assurance in affirmative health attentiveness in the past few decades. Therefore, it is essential to investigate various potential natural resources such as plants and microbes from where food-grade colorants can be obtained. Several drawbacks such as low water solubility, instability to light, heat, or adverse pH are associated with natural pigments extracted from plants. On the contrary, microbial pigments having higher stability and productivity are considered a potential alternative to synthetic dyes. Prodigiosin is a linear tripyrrole natural red pigment obtained from Serratia marcescens which is produced as a secondary metabolite. Prodigiosin and their derivatives act as proapoptotic agents against diverse cancer cell lines and also play a vital role in numerous cellular targets, including multi-drug resistance cells with reduced or no reported adverse side effects. Owing to its high potential in various sectors, there is an urgent need to explore and exploit the biosynthesis of prodigiosin using various biotechnological approaches. Furthermore, multifarious aspects in commercial-scale production of prodigiosin along with its contemporary utilization have been critically assessed in this article.

Production of prodigiosin by a drug-resistant Serratia rubidaea HB01 isolated from sewage

Production of green pigments has drawn great attention recently in various applications like foods, cosmetics, nutraceuticals, and pharmaceuticals as it counters the harmful effects of synthetic dyes. Use of green natural products, especially microbe-derived colours in food and cosmetics is rapidly developing for its eco-friendly nature and cost effectiveness. In this study, a red pigment producing rod-shaped, Gram-negative bacterium Serratia rubidaea HB01 was isolated from domestic sewage. The isolate exhibited wide resistance to various groups of antibiotics, including Aminoglycosides, Lincosamides, Macrolides, Nitroimidazoles, Penicillins, Quinolones, and Tetracyclines. The isolate S. rubidaea HB01 significantly produced red prodigiosin pigment (17.9 mg ml−1). The production of prodigiosin was highly pH sensitive and growth media specific. The UV–Vis spectrum of the red pigment dissolved in methanol showed a maximum absorption at 536 nm in neutral pH. Red fraction with Rf value 0.38 purified by thin layer chromatography (TLC) was further subjected to liquid chromatography and mass spectrometric (LC–MS) analysis. Moreover, a strong band of pyrrolenine (C = N) at vmax 1639 was found comparable to prodigiosin as observed from Fourier-transform infrared (FTIR) spectra. Alongside, the presence of a typical methoxy group with chemical shifts at δ 4.0 ppm and δ 58.5 ppm was revealed by 1H and 13C nuclear magnetic resonance (NMR) spectra respectively, confirming the red pigment produced to be prodigiosin. The molecular weight of the prodigiosin was identified as 323 (m/z 324, [M + H]+). Serratia species that typically develop antibiotic resistance mechanisms are already known to produce antibiotics (carbapenem and bacteriocins) and prodigiosin pigment by integrating Quorum Sensing (QS) with overlapping pigment production regulatory systems (pigP). Consequently, mutations in this regulatory region may influence the production of prodigiosin and antibiotic resistance mechanisms.

Optimization of prodigiosin biosynthesis by Serratia marcescens using unconventional bioresources

BackgroundProdigiosin is a naturally occurring red pigment by Serratia marcescens and having enormous medicinal properties. Recently, there is a need to develop a high-throughput and economically feasible bioprocess for the production of prodigiosin. In order to find a cost-effective alternative to individual fatty acids as substrate in industries, we tried to study the effect of different fatty acid containing oil seed cakes of peanut, sesame, and mustard as sources of substrate. The present study screened waste and unconventional bioresources for the production of prodigiosin using S. marcescens ATCC 13880. Sources with high oil content were screened for maximum production of prodigiosin. Also, various parameters like temperature, pH, and nutrient precursors were screened and optimized for the production of prodigiosin. ResultsScaled-up of optimized media consisting of 4% peanut oil seed cake powder, 2% sucrose, pH 7.5, temperature 28 °C, and 72 h incubation time resulted in highest production of 15.5 g/L wet biomass and 0.9 g/L of dried prodigiosin. Further, UV scan of the pigment showed maximum absorbance at 538 nm which is physiological property of the pigment. Extraction and purification of the pigment at the commercial level using the chromatographic techniques and mass spectral analysis confirmed the presence of prodigiosin. ConclusionUsing oil-extraction leftover wastes might help in the commercial and cost-effective production of prodigiosin.

Quorum sensing mediated response of Achromobacter denitrificans SP1 towards prodigiosin production under phthalate stress.

Quorum sensing is a density-dependent chemical process between bacteria, which may be intergenus or intragenus. N-acyl homoserine lactones (HSLs) are a type of small signaling molecules associated with Gram-negative bacteria for monitoring their own population density. The present study unveils the mechanism of HSLs in Achromobacter denitrificans SP1 while transforming di(2-ethylhexyl) phthalate (DEHP) into prodigiosin in a simple basal salt medium. The primary detection of HSLs was done by the colorimetric method. Fourier-transform infrared spectroscopy and liquid chromatography-mass spectrometry-quadrupole time-of-flight confirmed and identified the HSLs. The maximum production of HSLs was observed between 24 and 72 h of incubation, which is noted to be a peak time of DEHP degradation. A total of 57.2% of DEHP was degraded within 30 h and complete degradation was observed within 72 h of incubation. Regulation in the synthesis of various acyl-HSL molecules, viz. 3OC6-HSL in the initial stage of DEHP stress, 3OC8-HSL, and C10-HSL during the time of degradation and 3OC12-HSL on completion of degradation was noticed. The role of HSLs on the production of prodigiosin was confirmed using vanillin as an HSL inhibitor. Through the selective activation of HSL molecules, A. denitrificans SP1 sustain the changing stressful conditions. Supplementation of acyl-HSL signal molecules may boost up the efficacy of A. denitrificans SP1 in both DEHP degradation and prodigiosin production which offers great potential towards the management of DEHP containing plastic wastes.

Microbial Reclamation of Chitin and Protein-Containing Marine By-Products for the Production of Prodigiosin and the Evaluation of Its Bioactivities

Chitin and protein-containing marine by-products (CPCMBPs), including crab shells, squid pens, and shrimp shells, were investigated as the sole carbon/nitrogen (C/N) source for prodigiosin (PG) production by Serratia marcescens TNU01 in a 250 mL Erlenmeyer flask and a 10 L bioreactor system. Among the used C/N source of CPCMBPs, squid pens powder (SPP) showed the most optimum PG productivity. Different ratios of chitin/protein combination were also used as the C/N sources for PG production. With a similar chitin/protein ratio (4/6) of squid pens, a significant PG productivity was achieved when the chitin/protein ratios were controlled in the range of 3/7–4/6. Maximum PG yield (3450 mg/L) by S. marcescens TNU01 was achieved in the bioreactor system containing 3 L medium of 1.75% SPP, 0.03% K2HPO4, and 0.05% MgSO4 at 25 °C for 12 h in dark. The results of in vitro bioassays reveal that the purified PG possesses acetylcholinesterase inhibitory activity and antioxidant as well as anticancer activities. This study suggests that squid pens may have the potential to be used for cost effective production of bioactive PG at a large-scale.

Improved Prodigiosin Production by Relieving CpxR Temperature-Sensitive Inhibition.

Prodigiosin (PG) is a typical secondary metabolite mainly produced by Serratia marcescens. CpxR protein is an OmpR family transcriptional regulator in Gram-negative bacteria. Firstly, it was found that insertion mutation of cpxR in S. marcescens JNB 5-1 by a transposon Tn5G increased the production of PG. Results from the electrophoretic mobility shift assay (EMSA) indicated that CpxR could bind to the promoter of the pig gene cluster and repress the transcription levels of genes involved in PG biosynthesis in S. marcescens JNB 5-1. In the ΔcpxR mutant strain, the transcription levels of the pig gene cluster and the genes involved in the pathways of PG precursors, such as proline, pyruvate, serine, methionine, and S-adenosyl methionine, were significantly increased, hence promoting the production of PG. Subsequently, a fusion segment composed of the genes proC, serC, and metH, responsible for proline, serine, and methionine, was inserted into the cpxR gene in S. marcescens JNB 5-1. On fermentation by the resultant engineered S. marcescens, the highest PG titer reached 5.83 g/L and increased by 41.9%, relative to the parental strain. In this study, we revealed the role of CpxR in PG biosynthesis and provided an alternative strategy for the engineering of S. marcescens to enhance PG production.

RpoS is a pleiotropic regulator of motility, biofilm formation, exoenzymes, siderophore and prodigiosin production, and trade-off during prolonged stationary phase in Serratia marcescens.

Prodigiosin is an important secondary metabolite produced by Serratia marcescens. It can help strains resist stresses from other microorganisms and environmental factors to achieve self-preservation. Prodigiosin is also a promising secondary metabolite due to its pharmacological characteristics. However, pigmentless S. marcescens mutants always emerge after prolonged starvation, which might be a way for the bacteria to adapt to starvation conditions, but it could be a major problem in the industrial application of S. marcescens. To identify the molecular mechanisms of loss of prodigiosin production, two mutants were isolated after 16 days of prolonged incubation of wild-type (WT) S. marcescens 1912768R; one mutant (named 1912768WR) exhibited reduced production of prodigiosin, and a second mutant (named 1912768W) was totally defective. Comparative genomic analysis revealed that the two mutants had either mutations or deletions in rpoS. Knockout of rpoS in S. marcescens 1912768R had pleiotropic effects. Complementation of rpoS in the ΔrpoS mutant further confirmed that RpoS was a positive regulator of prodigiosin production and that its regulatory role in prodigiosin biosynthesis was opposite that in Serratia sp. ATCC 39006, which had a different type of pig cluster; further, rpoS from Serratia sp. ATCC 39006 and other strains complemented the prodigiosin defect of the ΔrpoS mutant, suggesting that the pig promoters are more important than the genes in the regulation of prodigiosin production. Deletion of rpoS strongly impaired the resistance of S. marcescens to stresses but increased membrane permeability for nutritional competence; competition assays in rich and minimum media showed that the ΔrpoS mutant outcompeted its isogenic WT strain. All these data support the idea that RpoS is pleiotropic and that the loss of prodigiosin biosynthesis in S. marcescens 1912768R during prolonged incubation is due to a mutation in rpoS, which appears to be a self-preservation and nutritional competence (SPANC) trade-off.

Optimization of Bioreactor Cultivation Parameters by Taguchi Orthogonal Array Design for Enhanced Prodigiosin Production

One of the major steps toward the industrialization of the microbial product(s) is to optimize the cultivation conditions at the large-scale bioreactor and successfully control the microbial behavior within a large scale production environment. Statistical Design of Experiment was proven to optimize a vast number of microbial processes to achieve robustness and explore possible interactions among the variables. In this research, Taguchi Orthogonal Array was applied to optimize the cultivation condition of a newly isolated Prodigiosin-producing marine bacterial strain, Serratia AM8887, at the bioreactor level. The two-steps fermentation process was applied; as the productivity was scaled up from shake flask level to a benchtop bioreactor (5L) and subsequently to an in-situ sterilization bioreactor system (20L); yielding a 7g/L of the pigment; compared to 100mg/L before optimization confirming that; applying Taguchi experimental design is a reliable and good positive option for the optimization of biotechnological processes. The produced pigment was purified and the chemical structure was revealed using Spectrophotometric, Mass Spectrum (MS), Fourier Transform InfraRed (FT-IR), and proton Nuclear Magnetic Resonance (1H-NMR) spectroscopy analysis. The biological activity including antibacterial (against multidrug resistance), antioxidants (against 1,1-diphenyl-2-picrilhydrazyl) and cytotoxicity to cancer cell lines (against breast cancer MCF-7 and liver cancer HepG-2) of the pigment were explored showing very characteristic features that could be helpful in food, pharmaceuticals, and/or textile industries

Characterization of KPC-Producing Serratia marcescens in an Intensive Care Unit of a Brazilian Tertiary Hospital

Serratia marcescens has emerged as an important opportunistic pathogen responsible for nosocomial and severe infections. Here, we determined phenotypic and molecular characteristics of 54 S. marcescens isolates obtained from patient samples from intensive-care-unit (ICU) and neonatal intensive-care-unit (NIUC) of a Brazilian tertiary hospital. All isolates were resistant to beta-lactam group antibiotics, and 92.6% (50/54) were not susceptible to tigecycline. Furthermore, 96.3% showed intrinsic resistance to polymyxin E (colistin), a last-resort antibiotic for the treatment of infections caused by MDR (multidrug-resistant) Gram-negative bacteria. In contrast, high susceptibility to other antibiotics such as fluoroquinolones (81.5%), and to aminoglycosides (as gentamicin 81.5%, and amikacin 85.2%) was found. Of all isolates, 24.1% were classified as MDR. The presence of resistance and virulence genes were examined by PCR and sequencing. All isolates carried KPC-carbapenemase (blaKPC) and extended spectrum beta-lactamase blaTEM genes, 14.8% carried blaOXA–1, and 16.7% carried blaCTX–M–1group genes, suggesting that bacterial resistance to β-lactam antibiotics found may be associated with these genes. The genes SdeB/HasF and SdeY/HasF that are associated with efflux pump mediated drug extrusion to fluoroquinolones and tigecycline, respectively, were found in 88.9%. The aac(6′)-Ib-cr variant gene that can simultaneously induce resistance to aminoglycoside and fluoroquinolone was present in 24.1% of the isolates. Notably, the virulence genes to (i) pore-forming toxin (ShlA); (ii) phospholipase with hemolytic and cytolytic activities (PhlA); (iii) flagellar transcriptional regulator (FlhD); and (iv) positive regulator of prodigiosin and serratamolide production (PigP) were present in 98.2%. The genetic relationship among the isolates determined by ERIC-PCR demonstrated that the vast majority of isolates were grouped in a single cluster with 86.4% genetic similarity. In addition, many isolates showed 100% genetic similarity to each other, suggesting that the S. marcescens that circulate in this ICU are closely related. Our results suggest that the antimicrobial resistance to many drugs currently used to treat ICU and NIUC patients, associated with the high frequency of resistance and virulence genes is a worrisome phenomenon. Our findings emphasize the importance of active surveillance plans for infection control and to prevent dissemination of these strains.

Effects of oil substrate supplementation on production of prodigiosin by Serratia nematodiphila for dye-sensitized solar cell

Bacterial pigments are potential substitute of chemical photosensitizer for dye-sensitized solar cell (DSSC) due to its non-toxic property and cost-effective production from microbial fermentation. Serratia nematodiphila YO1 was isolated from waterfall in Malaysia and identified using 16S ribosomal RNA. Characterization of the red pigment produced by the bacteria has confirmed the pigment as prodigiosin. Prodigiosin was produced from the fermentation of the bacteria in the presence of different oil substrates. Palm oil exhibited the best performance of cell growth and equivalent prodigiosin yield compared to olive oil and peanut oil. Prodigiosin produced with palm oil supplementation was 93 mg/l compared to 7.8 mg/l produced without supplementation, which recorded 11.9 times improvement. Specific growth rate of the cells improved 1.4 times when palm oil was supplemented in the medium. The prodigiosin pigment produced showed comparable performance as a DSSC sensitizer by displaying an open circuit voltage of 336.1 mV and a maximum short circuit current of 0.098 mV/cm2. This study stands a novelty in proving that the production of prodigiosin is favorable in the presence of palm oil substrate with high saturated fat content, which has not been studied before. This is also among the first bacterial prodigiosin tested as photosensitizer for DSSC application.

Green synthesis of silver nanoparticles using Carum copticum: Assessment of its quorum sensing and biofilm inhibitory potential against gram negative bacterial pathogens

Antimicrobial resistance among pathogenic bacteria has become a global threat to human health. Due to poor progress in development of new antimicrobial drugs, there is a need for the development of novel alternative strategies to combat the problem of multidrug resistance. Moreover, there is focus on ecofriendly approach for the synthesis nanoparticles having efficient medicinal properties including antivirulence properties to tackle the emergence of multi-drug resistance. Targeting quorum sensing controlled virulence factors and biofilms has come out to be a novel anti-infective drug target. The silver nanoparticles (Ag@CC-NPs) were synthesized from aqueous extract of Carum copticum and characterized using UV–vis absorption spectroscopy, fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Ag@CC-NPs were checked for its ability to inhibit quorum sensing-mediated virulence factors and biofilms against three test pathogens at sub-MIC values. There was ~75% inhibition of violacein production by Ag@CC-NPs against C. violaceum. The P. aeruginosa virulence factors such as pyocyanin production, pyoverdin production, exoprotease activity, elastase activity, swimming motility and rhamnolipid production were inhibited by 76.9, 49.0, 71.1, 53.3, 89.5, and 60.0% at sub-MIC. Moreover, virulence factors of S. marcescens viz. prodigiosin production, exoprotease activity, and swarming motility was reduced by 78.4, 67.8, and 90.7%. Ag@CC-NPs also exhibited broad-spectrum antibiofilm activity with 77.6, 86.3, and 75.1% inhibition of biofilms of P. aeruginosa, S. marcescens, and C. violaceum respectively. The biofilm formation on glass coverslip was reduced remarkably as evident from SEM and CLSM analysis. The findings revealed the in vitro efficacy of Ag@CC-NPs against bacterial pathogens and can be exploited in the development of alternative therapeutic agent in management of bacterial infections for topical application, mainly wound infection, or coating of surfaces to prevent bacterial adherence on medical devices.

Strategies for improved production of prodigiosin by Serratia mercences

Strategies for improved production of prodigiosin by Serratia mercences

Photoelectric evaluation of dye-sensitized solar cells based on prodigiosin pigment derived from Serratia marcescens 11E

Prodigiosin, a natural pigment produced as a secondary metabolite by the non-photosynthetic bacterium Serratia marcescens, was tested as a sensitizer in dye-sensitized solar cells (DSSC). The strain S. marcescens 11E, which was isolated from a natural spring located in the northeastern Mexican state of Nuevo Leon, was cultivated on peanut oil broth 1% v/v, a culture medium which is known to enhance the production of prodigiosin. The resulting pigment was extracted with chloroform and identified as prodigiosin based on the spectroscopic and structural characteristics obtained by UV–Vis spectrophotometry along with FTIR and 1H NMR spectroscopies. The initial absorbance decomposition test performed on the bacterial pigment demonstrated that prodigiosin exhibited high photostability after five days, while the photovoltaic performance test of the sensitized DSSC, resulted in an open voltage circuit of 560 mV, a current density of 0.096 mA/cm2, and efficiency of 0.032%. Structurally, the DSSC consisted of a titanium dioxide (TiO2) photoanode sensitized with the pigment by direct adsorption, an electrolyte containing a redox pair I−/I3− and a cathode or counter electrode prepared from a carbon paste. Since the overproduction of prodigiosin can be easily achieved on a large scale through the rapid fermentation of agro-industrial residues throughout the year without the need to allocate surfaces for the cultivation of pigment-producing plants or wait for specific seasons for their cultivation, our results suggest that prodigiosin could be considered an excellent candidate to be used in the development of a low-tech, low-cost DSSC.

Production of prodigiosin pigment by Serratia marcescens is negatively associated with cellular ATP levels during high-rate, low-cell-density growth.

Serratia marcescens is a facultatively anaerobic bacterium and the most recognized producer of the hydrophobic pigment prodigiosin. Previous work has shown that prodigiosin both increases ATP production during population lag phase and approximately doubles the stationary-phase cell yield. Here, we employed both batch and chemostat culture methods to investigate prodigiosin's role during high rate growth at low cell density as peak cellular ATP levels decline. Batch culture experiments utilizing artificial pigment induction showed an ATP reduction during low cell density growth. In addition, pigment induction during fixed growth rate chemostat culture revealed a negative correlation between cellular levels of prodigiosin and ATP (r = -0.95). Variable growth rate chemostat experiments showed an inverse relationship between ATP per cell and prodigiosin per cell during low-density growth but a direct relationship during high-density growth. Rate modeling of chemostat data quantified the pigment's effect on cellular levels of ATP for both population growth phases. Finally, prodigiosin production in a heterologous bacterium led to ATP decline. These data with intact cells complement the established in vitro proton import function of prodigiosin pigment and may indicate an energy-spilling function during high rate, low cell density growth.

Response surface optimization of prodigiosin production by phthalate degrading Achromobacter denitrificans SP1 and exploring its antibacterial activity

The role of various parameters like temperature, pH, blood bag concentration, agitation and incubation that influence the production of prodigiosin by Achromobacter denitrificans SP1 was determined. The Plackett–Burman and Box–Behnken experimental designs were employed to statistically optimize and find out the best combinational effect of parameters for the better yield of prodigiosin using blood bag as sole carbon and energy source for the growth of A. denitrificans SP1. The maximum (1.314 mg/ml) prodigiosin production was attained at a temperature of 24 °C, pH (8.8), and blood bag (1 g) as optimum; while the predicted value was 1.319 mg/ml with a correlation coefficient of 0.987; which signifies the fitness of the model. Antimicrobial activity of the prodigiosin was also evaluated and found to be an effective agent against bacterial pathogens including Staphylococcus aureus and Proteus mirabilis. Utilization of the plasticizer di (2-ethylhexyl)phthalate (DEHP) in blood bag and the production of antibacterial prodigiosin makes A. denitrificans SP1, an effective competitor toward the pathogenic bacterial disinfection and wastewater treatment processes.