Violet pigment production from liquid pineapple waste by Chromobacterium violaceum UTM5 and evaluation of its bioactivity

Synthetic pigments have been utilized in numerous industries including textile, cosmetic, food and pharmaceuticals. However, the drawbacks of these pigments, namely toxicity problems have kindled interest in natural pigments. In view of this, the use of natural pigments such as those from a bacterial origin offers an interesting alternative for industrial application. However, large scale applications of natural pigments are often hindered by the high production cost. This study evaluates the feasibility of using liquid pineapple waste for the production of violacein by a locally isolated Chromobacterium violaceum UTM5 both in a shake flask and a 50 L bioreactor. The use of optimized growth parameters including culture conditions, concentration of liquid pineapple waste and supplementation of l-tryptophan resulted in a violacein yield of 16 256 ± 440 mg L-1. Post treatment of the effluent effectively reduced the COD, turbidity and TSS contents to less than 1 mg L-1, 1.57 ± 0.2 NTU and 2.7 ± 0.6 mg L-1 respectively. The violet pigment exhibited good stability during the entire storage period of 30 days at pH 7, temperature 25-30 °C and under dark conditions. The violet pigment has a good antimicrobial activity against selected microorganisms. Of interest, the pigment was active against Staphylococcus aureus ATCC 29213 and methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300 with a MIC value of 7.8 and 15.6 µg mL-1, respectively. However, the pigment is toxic to the V79-4 Chinese hamster lung cells with low selectivity index. The purified compounds were determined as violacein and deoxyviolacein respectively using FT-IR, LC-MS and NMR. The results confirmed the feasibility of using liquid pineapple waste as a potential low cost growth medium for the large-scale cultivation of violet pigment using C. violaceum UTM5

Synthesis and optimization of nano-sized bacterial-based violacein pigment using response surface methodology

Violacein from Chromobacterium violaceum has raised the enthusiasm of researchers in conducting comprehensive studies on these pigments due to their diverse biological activities including antibacterial and antioxidant properties. However, a limitation related with the solubility of the violacein pigment, by which it is commonly dissolved in toxic solvents such as dimethyl sulfoxide and methanol instead of being soluble in biological fluids and water. Hence, this study provides a method to synthesis the violacein pigment in nanoscale through an encapsulation technique using chitosan-tripolyphosphate (Cs-TPP) nanoparticles. The synthesis of nanoparticles in this study involved ionic gelation between chitosan and tripolyphosphate (TPP), in which several parameters were taken into consideration in order to control the size and dispersion stability of the violacein pigment in the suspension. Preparation parameters, including the concentration of chitosan, TPP and pigment as well as the mass ratio of chitosan to TPP, were optimized using Response Surface Methodology (RSM). Minimum particle size of 149.0 nm with zeta potential of +23.40 mV was obtained at the optimal formulations of 2.33 mg/mL of chitosan, 1.5 mg/mL of TPP, and 1 ppm of violacein pigment and at mass ratio of chitosan:TPP of 7:1. This nano-sized violacein pigment is expected to be applied as safe additive, colorant, and therapeutic agents. Meanwhile, RSM in the study could provide the optimal formulations for producing stable nano-sized violacein pigment

Spray drying of violet pigment from Chromobacterium violaceum UTM 5 and its application in food model systems

Spray drying is one of the well-established one-step processes of encapsulation technique to form micro particles. The concentrated violet pigment produced from Chromobacterium violaceum UTM 5 was encapsulated using Gum Arabic and spray dried under optimum conditions: atomizing air (1.15 kg/cm3), temperature feed rate (30 °C), air flow rate (60 m3/h), inlet (180 °C) and outlet (85 °C) temperatures to produce violet powder. On further investigation, the encapsulated pigment exhibited greatest stability during the entire storage period of 30 days at pH 7, temperature 25-60 °C and under dark condition. The violet powders produced were utilized in coloring food products, yogurt and jelly. Results confirmed promising use of this healthy natural colorant in food industry. This is the first report on spray drying of violet pigment from Chromobacterium violaceum and its potential for application in food items

Current perspective of yellowish-orange pigments from microorganisms- a review

Natural yellowish-orange pigments are derived from bacteria, yeasts, fungi and microalgae, including Chryseobacterium, Monascus and Chlorella. The purpose of this review is to provide an overview of these pigments in various aspects towards exploiting them for numerous functions. These pigments are produced in various shades of yellow-orange and categorised as carotenoids, anthraquinones, zeaxanthin, flexirubin and other compounds. They served as alternative colourants to replace hazardous and toxic synthetic pigments. Researchers are in progress to increase the pigment yield by improving the strains genetically, optimising the fermentation process and utilising cheap agro-industrial waste to reduce the production cost. Yellowish-orange pigments are applied in food, pharmaceuticals, cosmetics and textile industries. This review summarises the current technology status and challenges, economics, biosynthesis of pigment, novel strategies for production of yellowish-orange pigments, biological properties of pigments and metabolic engineering of microorganism with a focus on applications of pigments in food, pharmaceutical, dyeing industries as well as on other applications

Safety evaluation of flexirubin from Chryseobacterium artocarpi CECT 8497: acute, sub-acute toxicity and mutagenicity studies

Flexirubin has a broad range of pharmacological effects such as antimicrobial and anticancer activities. The aim of this study was to investigate the adverse effect of flexirubin (Chryseobacterium artocarpi CECT 8497) by acute, sub-acute (28. days repeated dose) oral toxicity and mutagenicity studies. The acute and sub-acute oral toxicity studies were performed in Sprague-Dawley rats (n - 12; male - 6; female - 6/group) as per OECD 425 (up and down procedure) and OECD 407 guidelines respectively. There was no mortality and signs of toxicity in acute and sub-acute toxicity studies. No test substance related differences were observed in body weight, food consumption, clinical signs, organ weight, haematology and serum biochemical parameters in treated groups of flexirubin at a target concentration of 1250, 2500 and 5000. mg/kg body weight per day for 28 days. The no-observed-adverse-effect level (NOAEL) of flexirubin was 5000. mg/kg body weight/day, the highest dose investigated. No evidence of mutagenicity was found, either in vitro (bacterial reverse mutation assay) or in vivo in mice (bone marrow micronucleus assay and sperm shape abnormality assay). The findings of this acute, sub-acute toxicity and mutagenicity studies support the safety of flexirubin extract

Antibacterial mode of action of violacein from Chromobacterium violaceum UTM5 against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA)

Violacein, violet pigment produced by Chromobacterium violaceum, has attracted much attention recently due to its pharmacological properties including antibacterial activity. The present study investigated possible antibacterial mode of action of violacein from C. violaceum UTM5 against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) strains. Violet fraction was obtained by cultivating C. violaceum UTM5 in liquid pineapple waste medium, extracted, and fractionated using ethyl acetate and vacuum liquid chromatography technique. Violacein was quantified as major compound in violet fraction using HPLC analysis. Violet fraction displayed bacteriostatic activity against S. aureus ATCC 29213 and methicillin-resistant S. aureus ATCC 43300 with minimum inhibitory concentration (MIC) of 3.9 μg/mL. Fluorescence dyes for membrane damage and scanning electron microscopic analysis confirmed the inhibitory effect by disruption on membrane integrity, morphological alternations, and rupture of the cell membranes of both strains. Transmission electron microscopic analysis showed membrane damage, mesosome formation, and leakage of intracellular constituents of both bacterial strains. Mode of action of violet fraction on the cell membrane integrity of both strains was shown by release of protein, K+, and extracellular adenosine 5′-triphosphate (ATP) with 110.5 μg/mL, 2.34 μg/mL, and 87.24 ng/μL, respectively, at 48 h of incubation. Violet fraction was toxic to human embryonic kidney (HEK293) and human fetal lung fibroblast (IMR90) cell lines with LC50 value of 0.998 ± 0.058 and 0.387 ± 0.002 μg/mL, respectively. Thus, violet fraction showed a strong antibacterial property by disrupting the membrane integrity of S. aureus and MRSA strains. This is the first report on the possible mode of antibacterial action of violet fraction from C. violaceum UTM5 on S. aureus and MRSA strains

Production of bacterial pigments in low cost medium and formulation of biodegradable ink

441-447Bacterial pigment production is an emerging field of research for its wide potential industrial applications. Prodigiosin (Serratia marcescens UTM1) and violacein (Chromobacterium violaceum UTM5) are such pigments which possess several biological properties and and have gained increasing importance in industrial markets such as drugs, cosmetics, textile dyeing, etc. The present study demonstrates the use of low cost medium for growth of locally isolated red, violet pigment producing bacteria and their application as biodegradable ink on plastic materials. The natural inks were successfully formulated using polyvinyl butyral, ethyl acetate, methyl ethyl ketone, and applied on plastic materials. They were able to withstand heat up to 60°C and showed no damage to plastic material during physical contact. The hue and chroma values showed the formulated natural inks falls within the red and violet colour. The results have shown that the bacterial pigments act as natural colourants and have great potential as biodegradable inks

Brown sugar as a low-cost medium for the production of prodigiosin by locally isolated Serratia marcescens UTM1

Interest in bacterial pigments such as prodigiosin is growing among researchers due to their antibacterial, antifungal, antiproliferative and immunosuppressive properties. However, commercial application of bacterial-based pigments such as prodigiosin is limited due to the high production cost, which is partly caused by the expensive growth medium. This study reports on the use of brown sugar for the growth of a locally isolated, red-pigment (prodigiosin)-producing bacterium, i.e. Serratia marcescens UTM1. Factors affecting prodigiosin production - notably culture conditions and the effect of lactose and L- tryptophan supplementation - were evaluated in both shake-flask and 5-l bioreactor conditions. The use of optimized conditions resulted in a high prodigiosin yield of ~8000mgl-1. The TLC and column chromatography-purified fraction was confirmed as prodigiosin using FTIR, LC-MS and NMR. This study demonstrates the feasibility of using brown sugar as a potential cheap growth medium for large-scale cultivation of prodigiosin using locally isolated S. marcescens UTM1

Current perspective on bacterial pigments: emerging sustainable compounds with coloring and biological properties for the industry - an incisive evaluation

The current inclination towards exploiting bacterial pigments for various coloring functions, like food, cloth, painting, cosmetics, pharmaceuticals, plastics etc. is a well-recognized aspect. Nevertheless, the current bacterial pigment productions are not effective to meet their industrial needs. Current research going on world over on bacterial pigments signify that genetic engineering for strain improvement, optimization of bioprocess modelling and utilizing cheap agro-industrial residues as substrates are key developmental strategies to maximize pigment production from bacteria. Incidentally the superior performance characteristics of the bacteria for producing differing colouring compounds and the environmental acceptability of bacterial pigments are very encouraging factors to promote higher pigment production taking advantage of the current developmental strategies. This paper evaluates the current advances in bacterial pigment production, its recovery and wide-ranging scope of its industrial applications and commercial viabilit