ABSTRACT
This study demonstrates that Lactobacillus can produce exopolysaccharides (EPSs) using alternative carbon sources, such as sugarcane molasses and glycerol. After screening 22 strains of Lactobacillus to determine which achieved the highest production of EPS based on dry weight at 37 °C, the strain Ke8 (L. casei) was selected for new experiments. The EPS obtained using glycerol and glucose as carbon sources was classified as a heteropolysaccharide composed of glucose and mannose, containing 1730 g.mol-1, consisting of 39.4% carbohydrates and 18% proteins. The EPS obtained using molasses as the carbon source was characterized as a heteropolysaccharide composed of glucose, galactose, and arabinose, containing 1182 g.mol-1, consisting of 52.9% carbohydrates and 11.69% proteins. This molecule was characterized using Size Exclusion Chromatography (HPLC), Gas chromatography-mass spectrometry (GC-MS), Fourier-transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance spectroscopy (1H-NMR). The existence of polysaccharides was confirmed via FT-IR and NMR analyses. The results obtained suggest that Lacticaseibacillus casei can grow in media that use alternative carbon sources such as glycerol and molasses. These agro-industry residues are inexpensive, and their use contributes to sustainability. The lack of studies regarding the use of Lacticaseibacillus casei for the production of EPS using renewable carbon sources from agroindustry should be noted.
ABSTRACT
Citrus canker is a disease caused by the gram-negative bacterium Xanthomonas citri subp. citri (X. citri), which affects all commercially important varieties of citrus and can lead to significant losses. Fruit sanitization with products such as chlorine-based ones can reduce the spread of the disease. While effective, their use raises concerns about safety of the workers. This work proposes essential oils (EOs) as viable alternatives for fruit sanitization. EOs from Cymbopogon species were evaluated as to their antibacterial activity, their effect on the bacterial membrane, and their ability to sanitize citrus fruit. The in vitro assays revealed that the EOs from C. schoenanthus and C. citratus had a lower bactericidal concentration at 312 mg L-1, followed by 625 mg L-1 for C. martini and C. winterianus. Microscopy assay revealed that the bacterial cell membranes were disrupted after 15 min of contact with all EOs tested. Regarding the sanitizing potential, the EOs with higher proportions of geraniol were more effective in sanitizing acid limes. Fruit treated with C. shoenanthus and C. martini showed a reduction of â¼68% in the recovery of viable bacterial cells. Therefore, these EOs can be used as viable natural alternatives in citrus fruit disinfection.
Subject(s)
Anti-Bacterial Agents , Citrus , Cymbopogon , Oils, Volatile , Plant Diseases , Xanthomonas , Cymbopogon/chemistry , Oils, Volatile/pharmacology , Xanthomonas/drug effects , Citrus/microbiology , Plant Diseases/microbiology , Plant Diseases/prevention & control , Anti-Bacterial Agents/pharmacology , Fruit/microbiology , Microbial Sensitivity TestsABSTRACT
Plant pathogens cause great economic losses in agriculture. To reduce damage, chemical pesticides have been frequently used, but these compounds in addition to causing risks to the environment and health, its continuous use has given rise to resistant phytopathogens, threatening the efficiency of control methods. One alternative for such a problem is the use of natural products with high antifungal activity and low toxicity. Here, we present the production, isolation, and identification of cyclopaldic acid, a bioactive compound produced by Penicillium sp. CRM 1540, a fungal strain isolated from Antarctic marine sediment. The crude extract was fractionated by reversed-phase chromatography and yielded 40 fractions, from which fraction F17 was selected. We used 1D and 2D Nuclear Magnetic Resonance analysis in DMSO-d6 and CDCl3, together with mass spectrometry, to identify the compound as cyclopaldic acid C11H10O6 (238 Da). The pure compound was evaluated for antimicrobial activity against phytopathogenic fungi of global agricultural importance, namely: Macrophomina phaseolina, Rhizoctonia solani, and Sclerotinia sclerotiorum. The antifungal assay revealed the potential of cyclopaldic acid, produced by Penicillium sp. CRM 1540, as a leading molecule against M. phaseolina and R. solani, with more than 90% of growth inhibition after 96h of contact with the fungal cells using 100 µg mL-1, and more than 70% using 50 µg mL-1. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03792-9.
ABSTRACT
Bacterial diseases caused by members of the genus Xanthomonas affect agricultural crops of great importance in the world. At least 350 different plant diseases are caused by species of Xanthomonas. Important crops, such as: rice, citrus, cassava, tomato, sugar cane, passionfruit and brassicas are severely affected by bacteria of this genus. Due to its rapid propagation, handling difficulties, problems with chemical control and severity of the losses of the affected plantations Xanthomonas is a difficult obstacle for agriculture around the world. In addition, chemical control of some of these diseases is carried out using copper-based chemicals, which causes a negative impact on health and the environment. A more sustainable alternative to combat these diseases is the control of Xanthomonas by microorganisms directly or indirectly through the use of its secondary metabolites involved in biocontrol. This review is a report concerning the recent advances in the search for microorganisms for the biocontrol of several Xanthomonas that are important for the world economy.
Subject(s)
Plant Diseases/microbiology , Plant Diseases/prevention & control , Xanthomonas/pathogenicity , Bacteria/metabolism , Biological Control Agents/metabolism , Biological Control Agents/pharmacology , Crops, Agricultural/microbiology , Fungi/metabolism , Pest Control, Biological/methods , Secondary Metabolism , Xanthomonas/classification , Xanthomonas/drug effects , Xanthomonas campestris/pathogenicityABSTRACT
Bacillus coagulans arr4 is a thermotolerant microorganism with great biotechnological potential for l-(+)-lactic acid production from granulated sugar and yeast extract. The highest l-(+)-lactic acid production was obtained with Ca(OH)2. The maximum production of l-(+)-lactic acid (206.81 g/L) was observed in exponential feeding using granulated sugar solution (900 g/L) and yeast extract (1%) at 50 °C, pH 6.5, and initial granulated sugar concentration of 100 g/L at 39 h. 5.3 g/L h productivity and 97% yield were observed, and no sugar remained. Comparing the simple batch with exponential fed-batch fermentation, the l(+) lactic acid production was improved in 133.22% and dry cell weight was improved in 83.29%, using granulated sugar and yeast extract. This study presents the highest productivity of lactic acid ever observed in the literature, on the fermentation of thermotolerant Bacillus sp. as well as an innovative and high-efficiency purification technology, using low-cost substances as Celite and charcoal. The recovery of lactic acid was 86%, with 100% protein removal, and the fermentation medium (brown color) became a colorless solution.
ABSTRACT
The interest in the production of lactic acid has increased due to its wide range of applications. In the present study, the variables that affect fermentative D(-) lactic acid production were investigated: neutralizing agents, pH, temperature, inoculum percentage, agitation, and concentration of the medium components. An experimental design was applied to determine the optimal concentrations of the medium components and fermentation was studied using different feeding strategies. High production (122.41 g/L) and productivity (3.65 g/L·h) were efficiently achieved by Sporolactobacillus nakayamae in 54 h using a multipulse fed-batch technique with an initial medium containing 35 g/L of yeast extract (byproduct of alcohol production), 60 g/L of crystallized sugar, and 7.5 mL/L of salts. The fermentation process was conducted at 35°C and pH 6.0 controlled by NaOH with a 20% volume of inoculum and agitation at 125 rpm. The production of a high optically pure concentration of D(-) lactic acid combined with an environmentally friendly NaOH-based process demonstrates that S. nakayamae is a promising strain for D(-) lactic acid production.
ABSTRACT
ABSTRACT Lactic acid, which can be obtained through fermentation, is an interesting compound because it can be utilized in different fields, such as in the food, pharmaceutical and chemical industries as a bio-based molecule for bio-refinery. In addition, lactic acid has recently gained more interest due to the possibility of manufacturing poly(lactic acid), a green polymer that can replace petroleum-derived plastics and be applied in medicine for the regeneration of tissues and in sutures, repairs and implants. One of the great advantages of fermentation is the possibility of using agribusiness wastes to obtain optically pure lactic acid. The conventional batch process of fermentation has some disadvantages such as inhibition by the substrate or the final product. To avoid these problems, this study was focused on improving the production of lactic acid through different feeding strategies using whey, a residue of agribusiness. The downstream process is a significant bottleneck because cost-effective methods of producing high-purity lactic acid are lacking. Thus, the investigation of different methods for the purification of lactic acid was one of the aims of this work. The pH-stat strategy showed the maximum production of lactic acid of 143.7 g/L. Following purification of the lactic acid sample, recovery of reducing sugars and protein and color removal were 0.28%, 100% and 100%, respectively.
Subject(s)
Lactic Acid/biosynthesis , Lacticaseibacillus rhamnosus/metabolism , Industrial Waste , Temperature , Biodegradation, Environmental , Biotransformation , Adsorption , Fermentation , Batch Cell Culture Techniques , Hydrogen-Ion ConcentrationABSTRACT
Lactic acid, which can be obtained through fermentation, is an interesting compound because it can be utilized in different fields, such as in the food, pharmaceutical and chemical industries as a bio-based molecule for bio-refinery. In addition, lactic acid has recently gained more interest due to the possibility of manufacturing poly(lactic acid), a green polymer that can replace petroleum-derived plastics and be applied in medicine for the regeneration of tissues and in sutures, repairs and implants. One of the great advantages of fermentation is the possibility of using agribusiness wastes to obtain optically pure lactic acid. The conventional batch process of fermentation has some disadvantages such as inhibition by the substrate or the final product. To avoid these problems, this study was focused on improving the production of lactic acid through different feeding strategies using whey, a residue of agribusiness. The downstream process is a significant bottleneck because cost-effective methods of producing high-purity lactic acid are lacking. Thus, the investigation of different methods for the purification of lactic acid was one of the aims of this work. The pH-stat strategy showed the maximum production of lactic acid of 143.7g/L. Following purification of the lactic acid sample, recovery of reducing sugars and protein and color removal were 0.28%, 100% and 100%, respectively.
Subject(s)
Industrial Waste , Lactic Acid/biosynthesis , Lacticaseibacillus rhamnosus/metabolism , Adsorption , Batch Cell Culture Techniques , Biodegradation, Environmental , Biotransformation , Fermentation , Hydrogen-Ion Concentration , TemperatureABSTRACT
Sesquiterpene lactones are known to be active, but are also known to present high cytotoxicity. In the present work an evaluation of how slight structural alterations affect the cytotoxicity and the schistosomicidal activity of sesquiterpene lactones was undertaken. More specifically, we assessed the activity of budlein-A, a furanoheliangolide sesquiterpene lactone, and four of its derivatives. The structural modifications of budlein-A, presented in this work, diminished the cytotoxicity and changed the antiparasitary behavior of the molecule. They also provided data for a better understanding of the sesquiterpene lactone cytotoxicity. The establishment of the structures of three synthesized sesquiterpene lactones on the basis of NMR and HRESIMS data is also presented here. Complete and detailed (1)H and (13)C 1D and 2D NMR data, with measurements of all J values and all multiplicities clarified, are presented for five sesquiterpene lactones for the first time.
Subject(s)
Antiparasitic Agents/pharmacology , Biological Products/pharmacology , Lactones/pharmacology , Schistosoma mansoni/drug effects , Schistosomicides/pharmacology , Sesquiterpenes/pharmacology , Animals , Antiparasitic Agents/chemical synthesis , Antiparasitic Agents/chemistry , Biological Products/chemical synthesis , Biological Products/chemistry , Biomphalaria , Cell Line , Cell Survival/drug effects , Dose-Response Relationship, Drug , Humans , Lactones/chemical synthesis , Lactones/chemistry , Magnetic Resonance Spectroscopy , Mice , Molecular Structure , Parasitic Sensitivity Tests , Schistosomicides/chemical synthesis , Schistosomicides/chemistry , Sesquiterpenes/chemical synthesis , Sesquiterpenes/chemistry , Structure-Activity RelationshipABSTRACT
The solvent has a significant influence in the rate of reactions promoted by Stryker's reagent. The reactions performed in THF were, in most cases, faster than in toluene.