Pigment Production Research Articles

Semi-commercial scale fermentation of prawn waste by Exiguobacterium sp. GM010 for bioactive pigment production: Safety and efficacy assessment in Wistar rats

Pigment producing Exiguobacterium sp. GM010 demonstrates utilization of prawn carapace hydrolysate. Accordingly, our investigation was focused to produce cost effective bioactive pigment in 15 L semi-commercial scale. Further acute and subacute toxicities were evaluated as per OECD guidelines for application as nutraceutical. The biomass and pigment extract yield were 28.76 ± 1.78 and 0.82 ± 0.04 g/L, respectively, at 1.5 L of aeration. The UV–visible spectrum of pigment showed absorption peaks at 357, 466, and 491 nm indicating carotenoid like pigment. This was correlated with colour distribution in yellowish-orange region of CIE Lab spectrum. The qualitative and quantitative characteristics of pigment were similar between lab-scale and bioreactor production. The acute toxic dose (2000 mg/kg bw) exhibited the toxicity as determined by haematological analysis. While subacute toxic dose (250, 500, 1000 mg/kg bw) demonstrated no adverse effects on parameters such as food intake, body weight gain, vital organ weight, haematological and histopathological examination. Serum biochemistry results showed significant increase in HDL and decrease in SGPT values in treated groups compared to control. The results revealed that, Exiguobacterium sp. GM010 has efficiently utilised prawn waste to produce bioactive pigment. The dose of Exiguobacterium sp. GM010 pigment lower than 1000 mg/kg bw can be regarded as safe.

Expression patterns of melanin-related genes are linked to crypsis and conspicuousness in a pumpkin toadlet.

Colour signals play pivotal roles in different communication systems, and the evolution of these characters has been associated with behavioural ecology, integumentary production processes and perceptual mechanisms of the species involved. Here, we present the first insight into the molecular and histological basis of skin colour polymorphism within a miniaturized species of pumpkin toadlet, potentially representing the lowest size threshold for colour polytypism in tetrapods. Brachycephalus actaeus exhibits a coloration ranging from cryptic green to conspicuous orange skin, and our findings suggest that colour morphs differ in their capability to be detected by potential predators. We also found that the distribution and abundance of chromatophores are variable in the different colour morphs. The expression pattern of coloration related genes was predominantly associated with melanin synthesis (including dct, edn1, mlana, oca2, pmel, slc24a5, tyrp1 and wnt9a). Up-regulation of melanin genes in grey, green and brown skin was associated with higher melanophore abundance than in orange skin, where xanthophores predominate. Our findings provide a significant foundation for comparing and understanding the diverse pathways that contribute to the evolution of pigment production in the skin of amphibians.

FTY720 Reduces the Biomass of Biofilms in Pseudomonas aeruginosa in a Dose-Dependent Manner.

Pseudomonas aeruginosa, a nosocomial pathogen, has strong biofilm capabilities, representing the main source of infection in the human body. Repurposing existing drugs has been explored as an alternative strategy to combat emerging antibiotic-resistant pathogens. Fingolimod hydrochloride (FTY720), an immunomodulatory drug for multiple sclerosis, has shown promising antimicrobial effects against some ESKAPE pathogens. Therefore, the effects of FTY720 on the biofilm capabilities of Pseudomonas aeruginosa were investigated in this study. It was determined that FTY720 inhibited the growth of P. aeruginosa PAO1 at 100 µM. The significant reduction in PAO1 cell viability was observed to be dose-dependent. Additional cytotoxicity analysis on human cell lines showed that FTY720 significantly reduced viabilities at sub-inhibitory concentrations of 25-50 µM. Microtiter assays and confocal analysis confirmed reductions in biofilm mass and thickness and the cell survivability ratio in the presence of FTY720. Similarly, virulence production and biofilm-related gene expression (rhlA, rhlB, pilA, pilI, fliC, fliD and algR) were determined. The results demonstrate that pigment production was affected and quantitative real-time PCR analysis showed a variable degree of reduced gene expression in response to FTY720 at 12.5-50 µM. These findings suggest that FTY720 could be repurposed as an alternative antibiofilm agent against Pseudomonas aeruginosa.

Natural dyes developed by microbial-nanosilver to produce antimicrobial and anticancer textiles

Developing special textiles (for patients in hospitals for example) properties, special antimicrobial and anticancer, was the main objective of the current work. The developed textiles were produced after dyeing by the novel formula of natural (non-environmental toxic) pigments (melanin amended by microbial-AgNPs). Streptomyces torulosus isolate OSh10 with accession number KX753680.1 was selected as a superior producer for brown natural pigment. By optimization processes, some different pigment colors were observed after growing the tested strain on the 3 media. Dextrose and malt extract enhanced the bacteria to produce a reddish-black color. However, glycerol as the main carbon source and NaNO3 and asparagine as a nitrogen source were noted as the best for the production of brown pigment. In another case, starch as a polysaccharide was the best carbon for the production of deep green pigment. Peptone and NaNO3 are the best nitrogen sources for the production of deep green pigment. Microbial-AgNPs were produced by Fusarium oxysporum with a size of 7–21 nm, and the shape was spherical. These nanoparticles were used to produce pigments-nanocomposite to improve their promising properties. The antimicrobial of nanoparticles and textiles dyeing by nanocomposites was recorded against multidrug-resistant pathogens. The new nanocomposite improved pigments' dyeing action and textile properties. The produced textiles had anticancer activity against skin cancer cells with non-cytotoxicity detectable action against normal skin cells. The obtained results indicate to application of these textiles in hospital patients’ clothes.

Identification of Bacteria Producing Red Pigments and Their Application in the Textile Industry

AbstractIn this study, bacterial strains previously isolated and maintained in a culture collection were evaluated for their pigment production capabilities. The pigments produced by the bacteria were using the methanol extraction method and characterized by thin-layer chromatography, UV–Vis, and Fourier transform infrared spectroscopy (FTIR). In addition, the potential use of these pigments as textile dyes in silk fabrics was investigated. Four of the 270 isolates screened (AS-54, AS-55, AS-67, and AS-75) showed superior pigment production. These isolates were further identified using both classical and molecular methods. Based on the analysis of the 16S rRNA gene region, AS-54, AS-55, and AS-67 were identified as Serratia plymuthica and, AS-75 as Serratia marcescens. Characterization results showed that the pigments exhibited a red coloration, indicating prodigiosin. The dyeing of silk fabrics with these pigments resulted in various shades of pink, highlighting their potential as textile dyes. These results suggest that pigments derived from these bacterial isolates hold great promise for applications in the textile industry.

Evaluation of Dunaliella salina Growth in Different Salinities for Potential Application in Saline Water Treatment and Biomass Production

This study investigated the adaptability of Dunaliella salina to different salinity levels, with an emphasis on growth, pigment concentration, and desalination potential. It was found that among the 21 salinity levels, Salinity 75 produced consistently favorable results in cell count (13.08 × 103 ± 1.41 × 103 cells/mL), dry biomass (2.46 ± 0.06 g/L), pigment content (chlorophyll a = 97,500,000 ± 100,000 pg/L, chlorophyll b = 123,600,000 ± 300,000 pg/L), and desalination (9.32 ± 0.47 reduction). Therefore, Salinity 75 was selected for the final trial (scale-up), which revealed unanticipatedly high cell counts (58.96 × 103 ± 535.22 cells/mL), with the dry biomass weight being statistically different (higher) than expected (4.21 ± 0.02 g/L) (p < 0.0001), most likely due to the high cell count and energy reserve storage for high-salinity adaption in the form of bio-compounds. Pigment growth continued (chlorophyll a = 95,400,000 ± 2,200,000 pg/L, chlorophyll b = 128,100,000 ± 5,100,000 pg/L), indicating pigment production under salt stress. Notably, desalination did not occur in this stage, possibly due to the necessity for a bigger initial inoculate, prolonged exposure or bioaccumulation becoming the prevailing mechanism over desalination. Nevertheless, the trial highlights D. salina’s strong adaptation to various salinity levels. This suggests a promising future in halophyte research, particularly in understanding the mechanisms that prevent salt accumulation in cells and how to overcome this barrier. Additionally, these results suggest that microalgae could be a viable resource in saline-rich environments unsuitable for conventional agriculture, promoting industrial adaptation to adverse conditions.

Isolation and identification of Pseudomonas aeruginosa obtained from dogs and cats in Great Cairo regarding status of phenotypic antimicrobial resistance pattern

Background Companion animals; dog and cat are closely associated with the daily life of humans and may be implemented in the transmission of many microorganisms to their adopters. Pseudomonas aeruginosa (P. aeruginosa) is a suited opportunistic and harsh to treat pathogen due to its rife environmental distribution, unique intrinsic and acquired resistance to numerous antimicrobials’ categories. Objective The current study targeted to survey the existence of P. aeruginosa in laboratory samples obtained from diseased dogs and cats. The study also investigated the susceptibility and resistance of recovered isolates against antimicrobials. Materials and methods A total of 315 samples gathered from veterinary laboratories in Great Cairo governorates; fecal, ear, eye, respiratory, wounds and urine samples were previously collected from diseased dogs and cats. The samples were examined bacteriologically and biochemically to isolate P. aeruginosa. The isolates were assayed for their sensitivity and resistance versus 25 antimicrobials belonging to various categories. Results and conclusion Fifty- eight P. aeruginosa isolates (18.41%) were obtained from 315 dogs (44/233, 18.88%) and cats’ (14/82, 17.07%) clinical swabs. The isolates were confirmed biochemically and via VITEK 2 compact system. All isolates showed alpha-type of hemolysis and pigment production. The obtained P. aeruginosa isolates revealed a multidrug resistance pattern by 70.45% in dog isolates while cat isolates demonstrated a higher ratio 78.57%. P. aeruginosa isolates were highly resistant to cephalosporins, trimethoprim/sulfamethoxazole, and intermediate resistant to erythromycin fosfomycin. On the other hand imipenem, amikacin, azithromycin then gentamycin and ciprofloxacin were the most efficient on P. aeruginosa isolates. The study included that P. aeruginosa isolates obtained from canine and feline clinical samples collected from Great Cairo laboratories were characterized by high and intermediate levels of antimicrobial resistance. However, this pattern was directed to some classes of antibiotics, which are not authorized for veterinary use, which could expose an early warning mark and give the need for ongoing monitoring.

Investigation of Biofilm Formation, Anti-Quorum Sensing Activity and Antimicrobial Resistance in Corynebacterium Species Isolated from Clinical Samples

An increasing number of different clinical infections caused by Corynebacteria have been reported in the last decade. The aim of this study was to evaluate the antibiotic resistance rates, biofilm formation capacities and to investigate the ''anti-quorum-sensing (anti-QS)'' activities of corynebacteria, which were divided into three groups according to the type of growth in culture (pure, with another pathogenic bacterium and polymicrobial growth). In total 240 Corynebacterium spp. isolates from different clinical specimens sent to the medical microbiology laboratories of Düzce University Faculty of Medicine Hospital and Başakşehir Çam and Sakura City Hospital between June 2021 and June 2022 were classified into three groups: pure, isolated with another pathogen and polymicrobial, according to their growth patterns in culture. Bacteria were identified by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) Biotyper (Bruker, Germany) at an external centre. Antibiotic susceptibilities were determined by disc diffusion method and for vancomycin broth microdilution method was used. Results were interpreted according to EUCAST recommendations. The biofilm-forming properties of the isolates were determined quantitatively. Bioactive components of 17 isolates with strong biofilm formation were extracted and anti-QS activity was determined by agar diffusion method using Chromobacterium violaceum ATCC 12472 strain and then violacein pigment production was measured quantitatively. Of the 240 Corynebacterium spp. isolates, 138 (58%) were pure, 52 (22%) were isolated with another pathogen and 50 (20%) were part of a polymicrobial infection. Of the isolates, 140 were identified as C.striatum, 34 as C.amycolatum and 24 as Corynebacterium afermentans. When the antibiotic resistance rates of the Corynebacterium isolates were analysed according to the groups, the resistance rates to rifampicin and tetracycline antibiotics were found to be statistically significantly lower in the polymicrobial group than in the other groups. The resistance rates to penicillin, clindamycin, ciprofloxacin, moxifloxacin, rifampicin, tetracycline and linezolid were 96.7%, 88.3%, 86.3%, 73.8%, 62.5%, 59.2% and 0.8%, respectively. While all isolates were susceptible to vancomycin, linezolid resistance was detected in two C.afermentans isolates. When the biofilm formation ability was analysed, it was observed that 87 (36.3%) isolates formed biofilm. The biofilm formation rate of the isolates in the polymicrobial growth group was lower than the other two groups. The anti-QS activity of 17 isolates with strong biofilm formation was investigated and none of the Corynebacterium extracts tested were found to have anti-QS activity (inhibition of violacein pigment production without inhibiting bacterial growth) in the QS study with C.violaceum, whereas five isolate extracts had antibacterial activity (inhibition of bacterial growth). Four of the bacterial extracts with antimicrobial activity belonged to C.amycolatum and one to C.afermentans. In conclusion, when both antibiotic resistance rates and biofilm formation rates were analysed, the corynebacteria growing in culture with another pathogen showed similar characteristics to the corynebacteria growing as a pure culture. Therefore, it was thought that corynebacteria growing with another pathogen should not be ignored. In addition, the antimicrobial effects of some corynebacterial extracts suggested that more QS studies should be carried out with microbiota bacteria.

Identification and Evaluation of Antagonistic Potential of Different fluorescent pseudomonads in Northern Plains of West Bengal

To achieve future food security, reliable crop protection will be critically important. Development of biological control for soil borne disease is accepted as a safe, durable and ecofriendly alternative for chemical management strategy. Pseudomonads possess many traits like production antibiotics, lytic enzymes, siderophores, hydrogen cyanide (HCN) that make them well suited as biocontrol and growth-promoting agents. An attempt was taken to isolate and identify different fluorescent Pseudomonads and to evaluate their antagonistic ability. Twelve fluorescent Pseudomonads isolates were collected from different crop rhizosphere from different locations of northern parts of West Bengal. Isolates characterized morphologically and biochemically. All the isolates were gram negative rods with smooth and glossy colony on kings B and nutrient agar medium with convex elevation but variation was found in respect to pigment production. A huge variation was found in respect to biochemical characterization. From the result of biochemical analysis, the isolated sp. can be identified as Pseudomonas fluorescens or Pseudomonas putida or Pseudomonas aeruginosa. Some of the isolate produce green, some isolates produce yellowish green and rest of them produce red/pink pigments. Isolates showed a huge variation in respect to pathogenicity against soil borne pathogen Slerotium rolfsii. Percent inhibition varied from 31 to 74 %. Isolate 3 and 8 can be efficient biocontrol agent as highest growth inhibition of the pathogen Sclerotium rolfsii was obtained by the isolate 8 (74.37%) followed by isolate 3 (63.15%). In respect to growth parameter isolate 8, 9 and 10 were found better among the isolates where as in respect to disease reduction isolate 3, 8, 9 and 11 were promising under in vivo study.

Pigment Production From Bacteria Isolated From Whey

Pigment Production From Bacteria Isolated From Whey

STRATEGIES OF TOXIC CHROMIUM (VI) MITIGATION FROM TANNERY EFFLUENTS: A REVIEW

Hexavalent chromium i.e., Cr (VI) is highly toxic and carcinogenic it enters the environment through several anthropogenic activities. It is spuriously used in various industrial operations (leather tanning, electroplating, paint and pigment production etc.) because of its hardness and stability. It is found in industrial effluents in concentrations much above the prescribed limit of the World Health Organization (50 µg/L). Detection and remediation of chromium has been the subject of research of many scientists but many previous review works have been insufficient in comprehensive information. This review conveys the basic knowledge of chromate toxicity leading to physical discomfort and sometimes life-threatening illness including irreversible damage to the vital body system in humans. Conventional methods for removing toxic chromium ions (by chemical reduction followed by precipitation, ion- exchange and adsorption on activated coal, alum, kaolinite and ash) are costly for large-scale treatment. Microbial uptake followed by reduction of toxic Cr (VI) has become very successful due to its cost-effectiveness and use as a non-toxic agent. This is referred to as bioremediation. This review emphasises various strategies for hexavalent chromium bioremediation from contaminated water. This review article, therefore, tries to highlight this aspect of bioremediation of Cr (VI) from industrial effluents by native, indigenously resident chromate-resistant bacteria.

Antimicrobial Effect of Response Surface Optimized Pyocyanin Produced by Pseudomonas aeruginosa

Pseudomonas aeruginosa is notable for its natural bluish-green pigment production, known as pyocyanin. Researchers have credited pyocyanin as an antimicrobial agent, in addition to its other biomedical applications. This study focused on isolating Pseudomonas aeruginosa from the local environment with the ability to synthesize pyocyanin and optimize its cultural conditions for improved yield. A total of thirty-one experimental combinations of process variables using the Central Composite Design (CCD) of Response Surface Methodology (RSM) was ran to find the best conditions for the organism to make pigments. Of the fermentation media evaluated, nutrient broth supplemented with maltose was the best fermentation medium for the organism’s pyocyanin production. A regression model described the interaction between the test variables and the pyocyanin yield with an R2 value of 87.52%, indicating that the model had a satisfactory fitness level. The determined optimal conditions include a maltose concentration of 18 g/L, a pH of 6.8, an inoculum size of 2.3 mL, and an agitation speed of 120 rpm. The optimized condition resulted in a 4.12-fold increase in pyocyanin yield compared to an unoptimized condition. Pyocyanin exhibits high antimicrobial activity compared to the conventional antibiotics assessed against E. coli and Candida albicans. Our study’s findings suggest that statistical models can improve pyocyanin synthesis by Pseudomonas aeruginosa. Furthermore, this pigment has the potential to replace conventional antibiotics in the treatment of microbial infections

Kojic Acid Containing Novel Drug Delivery System on Facial Dyschromia: Characterization and Their Evaluation

Stubborn skin pigmentation issues like post-inflammatory hyperpigmentation (PIH) and melasma are the primary reasons people seek cosmetic consultations. Treating these conditions topically is challenging, as it involves inhibiting various stages of production of the pigment process. A powerful tyrosinase inhibitor like, kojic acid (KA) is employed as a formulation to regulate pigmentation production by suppressing the melanogenesis process. It’s important to note that the application of KA has been approved by the Food and Drug Administration (FDA), US, for dermatological treatments. The goal of this investigation was to formulate a nanoemulsion containing kojic acid for skin delivery using an emulsification method. The characteristics of the KA nanoemulsion were thoroughly examined through techniques like fourier transform infrared spectroscopy, (FTIR) particle size analysis and transmission electron microscopy (TME). In addition, the formulation’s performance was evaluated through both ex-vivo permeation study and in-vitro release study. Analysis of the FTIR, X-ray diffraction (XRD), and differential scanning calorimetry (DSC) results revealed that kojic acid with other ingredients in the formulation did not exhibit any chemical interactions. The kojic acid nanoparticles that were produced exhibited a spherical shape and were uniformly distributed, with an average size diameter of 184 nm. In in-vitro tests, it was observed that 87.67% of the drug was released within 12 hours. Moreover, ex-vivo permeation evaluation demonstrated that 81.24% of the drug permeated the skin within 8 hours of application. The thermal stability studies confirmed the stability of the kojic acid nanoemulsion, with no signs of creaming, cracking, or phase separation in the formulation. In conclusion, the findings of this study suggest that the kojic acid nanoemulsion holds great promise as an effective means for delivering kojic acid within the upper layers of the skin for treating of facial dyschromia.

Production and Extraction of Red Bioactive Pigment from Streptomyces griseorubiginosus and Formulation of Bio-Lip Balm

Production and Extraction of Red Bioactive Pigment from Streptomyces griseorubiginosus and Formulation of Bio-Lip Balm

A novel method of flash‐hydrolysis assisted pigment extraction (carotenoids) from microalgae biomass

AbstractThe human body can easily convert β‐carotene into retinol (a precursor of vitamin A), a significant ingredient in dietary supplements. The need for commercial natural pigment production, including β‐carotene, has led to intensive research in this area. Processing after biosynthesis is a vital stage that involves the use of nontoxic solvents, efficient mechanical disruption of cells, and the isolation of the required compounds. With the growing popularity of green extraction methods and the increasing market demand for carotenoids due to their health benefits, the use of clean, nontoxic, flash‐hydrolyzed biomass for carotenoid production presents a significant advantage. Furthermore, the remaining biomass can serve as a protein source for animal feed, thereby aligning with the principles of the biorefinery concept. In this study, our aim was to optimize the disruption of cells in two microalgal species using flash hydrolysis (FH). We applied two distinct levels of pressure and four separate temperature conditions over a brief residence time. Following this, we employed an ethanol extraction method to assess the efficiency of carotenoid pigment extraction. Flash hydrolysis is a chemical‐free subcritical water‐based continuous‐flow process, injected with wet biomass slurry at a high temperature (150–250 °C) for a very short time (8–12 s) to obtain bioproducts. In this study, we discovered that the pigment β‐carotene constituted 0.04 to 0.3% of the dry biomass in the case of Chlorella vulgaris. Bands of lutein and zeaxanthin were also observed in the thin layer chromatography (TLC) analysis of the treated slurry. This was achieved under conditions of an effective temperature of 200 °C and a pressure of 1700 psi. The Arthrospira platensis (1Tex), β‐carotene yield was 0.014 to 0.021% of dry biomass. Some lutein and zeaxanthin bands were also found in the treated slurry with an effective temperature of 150 °C and 1000 psi pressure. This study reports pigment extraction by FH for the first time. It is a viable process to scale up high‐value natural products like carotenoids from microalgae at the industrial level without adverse environmental impacts. Due to low residence time, the temperature does not have a negative effect on pigments; cell rupture was accomplished effectively using water as a solvent. A considerable amount of pigment could be recovered from microalgae at specific combinations of temperature and pressure depending on the type of cell wall that microalgae possess.

Enhancing immobilized Chlorella vulgaris growth with novel buoyant barium alginate bubble beads

Microalgae immobilization in alginate beads shows promise for biomass production and water pollution control. However, carrier instability and mass transfer limitations are challenges. This study introduces buoyant barium alginate bubble beads (BABB), which offer exceptional stability and enhance Chlorella vulgaris growth. In just 12 days, compared to traditional calcium alginate beads, BABB achieved a 20 % biomass increase while minimizing cell leakage and simplifying harvesting. BABB optimization involved co-immobilization with BG-11 medium, enrichment of CO2 in internal bubbles, and the integration of Fe nanoparticles (FeNPs). In the open raceway pond reactor, these optimizations resulted in a 39 % increase in biomass over 7 days compared to the unoptimized setup in closed flasks. Furthermore, enhancements in pigment and organic matter production were observed, along with improved removal of ammonia nitrogen and phosphate. These results highlight the overall advantages of BABB for microalgae immobilization, offering a scientific foundation for their effective utilization.

Brightening microalgal potential: A study on organic fluorescent dyes to increase photosynthetic active radiation

Microalgae hold promise for sustainable biomass and bioactive metabolite production, yet their commercial viability faces challenges due to low productivity, often linked to inefficient light utilisation. Algae absorb light primarily in the 400–500 nm (blue) and 600–700 nm (red) range termed photosynthetically active radiation (PAR), leaving excess light untapped. Optimising incident light spectra is vital for high biomass production. Recent advancements have utilised fluorescent dyes as spectral converters to improve PAR availability in algae. The current study evaluated the solubility and spectral profiles of Diphenylanthracene [DPA], Diphenyloxazole [DPO], Rhodamine 6G [R6G], Rhodamine 8G [R8G], Rhodamine 800 [R800], Fluorescein Isothiocyanate [FITC], Lumogen Yellow [LY], and Lumogen Red [LR] in methanol, ethanol, and acetone across varying concentrations. DPA and DPO absorbed UV light and emitted in violet/blue wavelengths. In contrast, R8G emitted light in the blue-green region (450–500 nm), which could potentially stimulate pigment and lipid production in algae. LY exhibited peaks covering green to red PAR wavelengths. LR dye displayed an excitation/emission range of 320–400 and 590–660 nm, whereas R6G, R800, and FITC showed no PAR-related emissions. Most dyes showed higher fluorescence at 10 mgL−1 in methanol. DPA, LY, and R8G displayed the highest energy emissions, with LR emitting 9.56 × 10−18 J·photon−1, suggesting its potential to supply ample energy for supporting algal growth. This spectral conversion strategy shows promise for enhancing microalgae growth and metabolite production, reducing reliance on artificial light, and potentially cutting energy and cultivation costs. The study contributes to advancing sustainable practices in algal biotechnology.

Sustained and enhanced inhibitory effects of allelochemicals on Microcystis Aeruginosa during its recruitment stage

Microcystis aeruginosa is the main toxic strain in cyanobacterial blooms, and the recruitment stage in its temperature-dependent seasonal succession is considered as the key to its subsequent growth. In this study, a protocol with specific temperature settings was developed as the simulated recruitment stage in order to investigate and confirm the superior inhibitory effects of allelochemicals on M. aeruginosa at that stage of recruitment. One of the most common allelochemicals, gallic acid (GA) (10 mg/L, 20 mg/L) was employed to treat M. aeruginosa under initially low temperature condition (15 °C), then intermediate (20 °C) and last normal (26 °C), which corresponds to the critical temperatures for cyanobacterial recruitment and growth. Growth, metabolism, photosynthetic activity, extracellular polysaccharides (EPS) and microcystins (MCs) release were analyzed and discussed in this study, and a more sustained and better inhibitory effect over a 20-day period was achieved. Notably, GA (10 mg/L) markedly delayed the recruitment of M. aeruginosa from low temperature, with an inhibition efficiency of 85.71 %, and suppressing Fv/Fm and photosynthetic pigments production. It is also observed that M. aeruginosa at recruitment stage exhibited higher sensitivity and poorer resistance to allelochemical treatment, with variable responses suggesting that optimal dosages may alter. The antioxidant enzyme activities remained high under prolonged stress, and the secretion of EPS was stimulated, indicating that cyanobacteria were more inclined to form colonies. While the laboratory-based inhibitory mechanism appeared to increase the release of microcystins in individual cells, the actual concentration of microcystins in natural aquatic environments requires further investigation.

Effect of selected bacteria of the genus Pseudomonas on the quality of raw cow’s milk

Pseudomonas spp. are a psychrotrophic species associated with milk spoilage caused by its enzymatic activities. The aim of this study was to identify Pseudomonas spp. in raw cow’s milk and to investigate their associated enzymatic properties and the ability to produce pyoverdine pigment. For microbiological analysis, 2 ml of milk samples was taken in sterile sample boxes. Milk sampling was carried out according to the principles of STN EN ISO 707. By identification using the PCR method, of n=320 samples of raw cow milk a total of 73 isolates of Pseudomonas spp. were identified as P. putida (34.25%); P. fragi (13.70%); P. lundensis (9.59%) and Pseudomonas spp. (42.47%). Proteolytic activity determined at a temperature of 7°C was positive from n=20 selected isolates of Pseudomonas spp. (60%) isolates and a temperature of 25°C was positively detected (85%). Lipolytic activity determined at a temperature of 7°C was confirmed in 35% of isolates and a temperature of 25°C it was confirmed in 70% isolates. Pyoverdine pigment production was detected in 65% of isolates. The results reveal the enzymatic activity of Pseudomonas spp. present in raw cow’s milk and its spoilage potential at different temperatures in relation to pigment production.

Eco-Dyeing and Functional Finishing of Cotton Fabric Using a Natural Colour Derived From Lotus Seed: Enhanced Fastness Properties with Chitosan

Medicinal plant-based dyeing introduces vibrant colours alongside antibacterial and anti-odor properties, fostering sustainability. Innovations include mass sampling for consistent pigment production. Furthermore, lotus seedpods, rich in bioactive compounds, exhibit potential in diverse fields. Chitosan, a biopolymer derived from chitin, boasts versatility in drug delivery systems, wound healing, and antimicrobial applications. This experimental inquiry delves into the dyeability and antimicrobial efficacy of cotton fabric subjected to treatment with chitosan and dyed using Lotus seeds. The investigation encompasses varied parameters such as dye concentration, duration, and temperature for fabric dyeing. The study elucidates the aqueous extraction methodology for dye from Lotus seeds, the chitosan-based mordanting techniques. Standardized assessments are utilized to gauge colour fastness characteristics, encompassing washing, rubbing, and perspiration fastness, along with assessing the antimicrobial attributes of the treated cotton fabric. The study indicates that the application of chitosan-treated cotton fabric enhances dye intensity and overall dyeing quality, consequently improving the colour fastness property of washing, rubbing, and perspiration. Additionally, the treated cotton fabric exhibits significant antimicrobial activity against common bacteria, highlighting the potential of Lotus seed-derived colourants and chitosan mordant in the development of sustainable and antimicrobial textiles. The future scope lies in optimizing the integration of Lotus seed-derived colourants and chitosan mordant for enhanced sustainability and antimicrobial efficacy in textile applications, leveraging advancements in dyeing technology and antimicrobial formulation techniques.