Soluble Phenolics Research Articles

​Optimization of Fermentation Factors for Vinegar Preparation from Sugarcane Jaggery using Response Surface Methodology

Background: Vinegar, an acidic functional fermentation product and known for its diverse health benefits was developed using liquid jaggery. A study was conducted to standardize the method of vinegar production from liquid jaggery using two different sugarcane varieties viz., CoH160 and Co89003. Methods: The submerged fermentation of liquid jaggery was carried out using yeast Saccharomyces cerevisiae and vinegar was produced using Acetobacter aceti. For the computation analysis of an optimized solution, a central composite rotatable design was applied which constituted three variables temperature (°C), inoculum concentration (%) and incubation time (days) and its influence on acetic acid percent as an important response was studied using Response Surface Methodology. Overall, twenty experimental trials were conducted as well as assessed on the vinegar quality indexes. Result: Vinegar prepared with 7.5 per cent inoculum concentration, incubated for a fermentation period of 12.5 days at 28.5°C was selected due to maximum acetic acid concentration achieved ( greater than 3.5% (w/v). The optimized vinegar contained total soluble solids (4.55-4.75 °Brix), reducing sugar (0.26-0.29%), total sugars (2.7-2.8%), titratable acidity (4.72-5.10%), pH (4.28-4.52), ascorbic acid (17.64-19.97%), alcohol content (0.68-0.79%), acetic acid (3.52-3.83%) and total phenols (36.69-38.22 mg/100 ml). The liquid jaggery vinegar had a bright yellow- brown color, cane flavor and vinegar aroma. It was found organoleptically acceptable.

Application of ligninolytic bacteria to the enhancement of lignocellulose breakdown and methane production from oil palm empty fruit bunches (OPEFB)

Efficient pretreatment of lignocellulosic biomass is needed to reduce associated energy costs. Lignin-degrading bacteria (Comamonas testosteroni, Agrobacterium sp., Lysinibacillus sphaericus, and Paenibacillus sp.) were tested as potential pre-treatment methods for oil palm empty fruit bunches (OPEFB) to enhance its methane yield during anaerobic digestion (AD). The lignocellulose fractions were analysed for total reducing sugar (TRS), total soluble phenols (TSP), lignin content, weight loss, pH and microscopic analysis carried out both before and after treatment. The methane production was tested using the biochemical methane potential (BMP) test. Bacteria mediated depolymerisation of OPEFB was confirmed through the observation of increased release of TSP and associated lignin breakdown and weight loss of the cultured OPEFB biomass. The highest percentage of lignin breakdown (25.84%) was obtained from OPEFB treated by Lysinibacillus sphaericus, while the highest average specific methane potential (0.042 m3/kg VS) was obtained from treatment with Comamonas testosteroni.

Mutational Analysis of a Wheat O-methyltransferase Involved in Flavonoid Metabolism.

Methylated flavones, and tricin in particular, have been implicated in protecting wheat plants against a variety of biotic and abiotic stresses. Methylated flavones are produced via O-methylation of the hydroxyl groups in flavones, which is catalyzed by O-methyltransferases (OMTs). To examine the role of wheat OMT2 in methylated flavone biosynthesis and facilitate interrogation of tricin functions in wheat-environment interactions, loss-of-function mutants of OMT2 homoeologs, omt-A2 and omt-B2, were identified from a tetraploid wheat Targeting Induced Local Lesions in Genomes (TILLING) mutant population and crossed to generate the omt-A2 omt-B2 double mutant. Although tricin and most other soluble phenolics did not differ in leaves and glumes of TILLING control and the omt-A2, omt-B2, and omt-A2 omt-B2 mutants, chlorogenic acid was increased in glumes of omt-A2 omt-B2 relative to TILLING control, suggesting that it might serve as a substrate for OMT2. The omt2 mutant lines showed similar growth phenotypes as well as comparable lignin deposition in cell walls of stems compared to TILLING control. These results collectively suggest that OMT2 and its close homolog OMT1 may possess overlapping activities in tricin production, with OMT1 compensating for the missing OMT2 activities in the omt2 mutant lines.

Photosynthetic efficiency, growth and secondary metabolism of common buckwheat (Fagopyrum esculentum Moench) in different controlled-environment production systems

Light-emitting diodes (LEDs) and high-pressure sodium lamps (HPS) are among the most commonly used light sources for plant cultivation. The objective of this study was to evaluate the effect of two controlled-environment production systems differing in light sources on growth, photosynthetic activity, and secondary metabolism of common buckwheat. We hypothesized that LED light with the majority of red and blue waves would increase physiological and biochemical parameters compared to sunlight supplemented with HPS lamps. The experiment was performed in a phytotronic chamber (LEDs) and in a greenhouse (solar radiation supplemented with HPS lamps as a control). The effects were analyzed at the flowering phase with biometric measurements, leaf chlorophyll index, the kinetics of chlorophyll a fluorescence, content of soluble carbohydrates and phenolics in the leaves. Applied LED light decreased the biomass but stimulated the production of phenolics compared to control plants. In control plants, a positive correlation between flavonoid content and energy dissipation from photosystem II (DIo/CSm) was found, while in plants under LEDs total pool of phenolic content correlated with this parameter and the quantum yield of electron transport (φ Ro and ψ Ro) was lower than that of the control, probably affecting buckwheat biomass.

Biochemical parameters and antioxidant property of three Salvia L. taxa endemic in Turkey.

The aim of the present study was to determine and compare the fatty acids, lipid soluble vitamins, sterols, phenolics, and antioxidant capacities of three endemic Salvia L. taxa (S. euphratica var. Montbret & Aucher ex Bentham leiocalycina (Rech. Fil.) Hedge, S. euphratica var. Montbret & Aucher ex Bentham euphratica (Rech. Fil.) Hedge and S. pseudoeuphratica Rech.Fil.) and to evaluate these results systematically. The fatty acid compositions were determined by using gas chromatography, while the lipid soluble vitamins, sterols, and phenolics were determined by using HPLC. Also, the antioxidant capacities of three Salvia taxa were measured in vitro. Palmitic acid was found as major saturated fatty acid while oleic acid, linoleic acid, α-linolenic acid, and erucic acid were found as major unsaturated fatty acids in the present study. It was found that S. euphratica var. euphratica had lower palmitic acid (8.94 ± 0.71%), total saturated fatty acid (19.16 ± 0.15%), and higher unsaturated fatty acid content (82.08 ± 0.52%) than other studied taxa. Furthermore, it was shown that S. euphratica var. euphratica had different 18.3/18:2 (0.36) unsaturated/saturated fatty acid (4.28) ratios. However, this study demonstrated that Salvia taxa had low lipid soluble vitamins, sterol contents. On the other hand, it was shown that Salvia taxa had similar catechin (509.2 ± 4.21 µg/g and 552.2 ± 9.21 µg/g) and vanillic acid amounts (351.2 ± 2.17 µg/g and 396.8 ± 4.1 µg/g) in this study. And also, it was found that Salvia taxa had high rosmarinic acid content while S. euphratica var. leiocalycina had the highest rosmarinic acid content (1480 ± 7.57 µg/g). On the other hand, it was shown that the two ferulic acid contents of S. euphratica varieties were higher (1175 ±/5.21 µgmg-1740.2 ± 4.82 µg/mg) than the ferulic acid content of S. pseudoeuphratica of which was the lowest (19.2 ± 0.97 µg/mg). The present results suggested that the biochemical results guided the morphological studies, and Salvia taxa have a potent antioxidant capacity.

Extraction and Analysis of Phenolic Compounds from Grape Berries.

Phenolics are ubiquitous compounds that represent the most abundant and diverse class of plant metabolites. From an analytical point of view, phenolics can be divided into soluble phenolics such as phenolic acids, phenylpropanoids, flavonoids and quinones, and nonsoluble compounds such as proanthocyanidins, lignins, and cell wall-bound hydroxycinnamic acids. Extraction of phenolics from the sample material is the first step toward their analysis. Biochemical methods for determination of total phenolics content were widely used in the past but modern chromatographic and mass spectrometric methods for identification and quantification of individual compounds are available in recent years. In this chapter, we describe methods for phenolic compounds extraction used in our laboratories from berries of Vitis vinifera and analytical methods including HPLC coupled to DAD detector and Q-TOF LC/MS for their analysis.

Application of two forms of silicon and their impact on the postharvest and the content of bioactive compounds in cucumber (Cucumis sativus L.) fruits

The metabolic activity of the fruits continues even after harvest, which results in the loss of bioactive compounds, a decrease in the quality of the fruits, softening and browning, among other negative effects. The use of certain elements such as silicon can improve postharvest quality, since it is involved in the metabolic, physiological and structural activity of plants, moreover can increase the quality of the fruits. In addition, nanotechnology has had a positive impact on crop yield, nutritional value, fruit quality and can improve antioxidant activity. For these reasons, the use of beneficial elements such as silicon in the form of nanoparticles can be a viable option to improve the characteristics of the fruits. In the present study was evaluated the application of potassium silicate (125, 250 and 500 mg L−1) and SiO2 nanoparticles (125, 250 and 500 mg L−1) during the development of the crop. The results showed that the application of silicon (potassium silicate and silicon nanoparticles) increased the content of total soluble solids (up to 15.6% higher than control), titratable acidity (up to 38.8% higher than control), vitamin C (up to 78.2% higher than control), phenols (up to 22% higher than control), flavonoids (up to 64.6% higher than control), and antioxidant activity in lipophilic compounds (up to 56.2% higher than control). This study suggests that the use of silicon can be a good option to increase the content of bioactive compounds in cucumber fruits when they are applied during the development of the crop.

Management of strawberry gray mold disease using some essential oils and molecular identification of pathogen fungus

Background Evaluation of preharvest application with some essential oils (EOs) for controlling gray mold disease of strawberry plants was studied.Objective In vitro trails, five EOs, that is, thyme, nerol, citral, methyl anthranilate, and clove oils, were evaluated for their capability to suppress fungal growth of Botrytis cinerea. At the National Center for Biotechnology Information, alignment showed the percentage of identity (100%) of B. cinerea between our isolates and Gene bank isolate.Materials and methods Five EOs were evaluated for their capability to suppress fungal linear growth of B. cinerea. Certain volume of each oil was added to autoclaved potato dextrose agar medium flasks to obtain the proposed concentrations of 00.0, 0.25, 0.5, and 1.0% with 0.1% Tween-80. Molecular identification using the internal transcribed spacer (ITS) region of rRNA Trimmed sequences (ITS 573 bp) was conducted.Results and conclusion B. cinerea isolate no. 3 was identified molecular using the ITS region of rRNA Trimmed sequences (ITS 573 bp) compared with different isolates of B. cinerea. All tested oils significantly reduced linear growth of B. cinerea fungus. Complete inhibition was obtained with concentration of 1.0% with all tested EOs and at 0.5% with thyme, citral, and methyl anthranilate, whereas concentration 0.25% showed moderate effect. Moreover, in vivo trails all tested EOs treatments at concentration of 0.5% significantly reduced disease incidence under natural infection. The most effective treatments are citral, methyl anthranilate, and thyme that reduced the disease incidence by 64.3%, 67.9%, and 67.9% on average at 5°C and 75.8%, 82.3%, and77.4% on average at 20°C, respectively, whereas other treatments showed moderate effect. The same trend was observed with disease severity. Meanwhile, under artificial infection, the highest reduction was obtained with citral, methyl anthranilate, and thyme that reduced the disease incidence by 68.2%, 75.0%, and 68.0% at 5°C and 76.0%, 77.0%, and 78.0% on average at 20°C, respectively. However, other treatments showed moderate effect. The same trend was observed with disease severity. As for fruit quality, all tested treatment had no negative effect on all tested characters of fruit quality. The most effective treatments are citral, methyl anthranilate, and thyme that reduced the decay incidence by 71.0%, 71.0%, and 69.3% and weight loss percentage by 79.4%, 78.2%, and 78.8%, respectively. Also, other treatments showed moderate effect, whereas methyl anthranilate, followed by thyme and clove increased the total soluble solid by 56.9%, 41.4%, and 36.2%, respectively. As for total soluble phenol, the highest increase was obtained with all tested oils. As for, titratable acidity, there are no significant differences between all tested treatments as compared with control fruits.

Ammonia–Nitrate Mixture Dominated by NH4+–N Promoted Growth, Photosynthesis and Nutrient Accumulation in Pecan (Carya illinoinensis)

Although ammonia–nitrogen (NH4+–N) and nitrate–nitrogen (NO3−–N) are the two main forms of N absorbed and utilized by plants, the preferences of plants for these forms are still unclear. In this study, we analyzed the growth, photosynthesis, and nutrients of pecan under different NH4+:NO3− ratios (0/0, 0/100, 25/75, 50/50, 75/25, 100/0) by indoor aerosol incubation. The results showed that additions of different N forms promoted the growth and development of pecan seedlings. When NO3−–N was used as the sole N source, it significantly promoted the ground diameter growth of pecan and increased the leaf pigment content and photosynthetic rate. The NH4+:NO3− ratio of 75:25 and NH4+–N as the sole N source significantly increased the soluble sugars in stems and roots, starch in leaves, stems and roots, soluble protein in leaves and stems, and soluble phenols in stems and roots. Additionally, the NH4+:NO3− ratio of 75:25 increased plant height, leaf number, root soluble protein, and leaf soluble phenol contents. In conclusion, regarding the physiological aspects of pecan growth, pecans are more inclined to use NH4+–N. Considering that the NH4+–N as the only N source may lead to nutrient imbalance or even toxicity, the NH4+:NO3− ratio of 75:25 was most favorable for the growth and development of pecan seedlings.

Boric acid as a potential substitute for conventional ethylene antagonists in mitigating postharvest flower senescence of Digitalis purpurea

Abstract In the floriculture industry, postharvest senescence is one of the glaring challenges restricting the marketability of cut flowers. Hence, maintaining good quality of cut flowers and extending flower longevity are considered to be the most crucial factors in the cut flower trade. Therefore, to gain better understanding of the specific physiological and biochemical aspects of petal senescence we conducted an experiment to evaluate the efficacy of Boric acid (BA) on flower longevity in excised flowers of Digitalis purpurea L. Isolated buds were harvested at stage IV i.e, 1 day before anthesis and divided into 5 sets, with one set of buds held in distilled water (DW) designated as control. The other 4 sets were supplemented with 24h pulse treatment of different concentrations of BA viz., 50, 100, 150 and 200 µM. The application of BA at 150 µM concentration was found to be most effective in increasing flower longevity by about 4 days as compared to control. The enhanced longevity coincided with higher values of floral diameter, fresh mass, dry mass and solution uptake. Flowers with delayed senescence also retained higher soluble proteins, sugars and phenols in addition to lower bacterial density compared to control. Moreover, this ameliorated flower longevity has also been shown to be positively associated with increased activities of various antioxidant enzymes viz., superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) and reduced activity of lipoxygenase (LOX).

Ethylene and its inhibitors affect the quality of processed sweet potatoes

Sweet potato fried chips have great acceptance and high market value. Sprouting and fresh mass loss of tuberous roots during storage compromise the quality of the processed products. The objective of this work was to evaluate the effect of 1-Methylcyclopropene (1-MCP), amino-oxyacetic acid (AOA), and ethylene on the physico-chemical quality of fresh sweet potato and its relationship with fried color score in processed chips of cv. BRS Rubissol stored at room temperature. During storage, the weight loss, sprouts number, dry matter content, non-enzymatic browning, protein content, soluble phenols fraction, reducing sugars, total amino acids, pH, soluble solids (SS), titratable acidity (TA) and SS/TA ratio were evaluated. The sweet potato roots cv. BRS Rubissol present good potential for processing as fried chips. 1-MCP and AOA treatments reduced the root sprouting, physico-chemical quality was maintained in all treatments and the fried chips showed less browning in all treatments with storage. Since the sprouting process compromises the storage of roots, AOA and 1-MCP treatments may be applied to extend the shelf-life of roots and improve the processing potential.

Evaluation of different antioxidants during in vitro establishment of allspice (Pimenta dioica L. Merrill): a recalcitrant species

Objective: To evaluate the effect of different antioxidant agents during in vitro establishment of allspice (Pimenta dioica L. Merrill). Design/methodology/approach: The effect of different antioxidant agents (Methylene blue, L-cysteine, and silver nanoparticles [AnNPs]) added to Murashige and Skoog culture medium at different concentrations were studied during axenic establishment of P. dioica. A completely randomized experimental design was used. All trials were performed in triplicate. The percentage of survival, oxidation, contamination was determined, the phenols content, antioxidant capacity and lipid peroxidation. Results: The highest survival occurred with the addition of L-cysteine. The lowest percentages oxidation were observed in explants treated with L-cysteine. Treatments with 100 and 200 mg L-1 AgNPs had the lowest contamination values. L-cysteine and 50 and 100 mg L-1 AgNPs resulted in an increase in the content of soluble phenols. The highest contents of cell wall-linked phenols were obtained in treatments with 200 mg L-1 methylene blue, L-cysteine, and 200 mg L-1 AgNPs. In this study, all treatments had a reaction of scavenging/reduction mechanisms free radicals. The highest content of malondialdehydes was observed in the control treatment and 200 mg L-1 methylene blue. The highest content of malondialdehydes was observed in the control treatment and 200 mg L-1 methylene blue. Limitations on study/implications: The highest percentage of oxidation was observed in the control treatments, 100 and 200 mg L-1 methylene blue, causing cell death. Findings/conclusions: The addition of L-cysteine to the culture medium is alternative to reduce oxidation during in vitro introduction of P. dioica.

Biochemical characterization of citrus bent leaf viroid infecting citrus cultivars

Citrus bent leaf viroid (CBLVd) is an emerging and widely distributed viroid along with its variants in citrus growing areas of world. Activation of defense mechanism is associated with different enzymes and inhibitors, accumulated in the infected host. Limited studies were found on biochemical characterization of citrus viroids. Therefore, study was focused on the biochemical activities such as determination of chlorophyll contents, total soluble phenolics (TSP), phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO) activity in three citrus cultivars kinnow (C. reticulate), feutrell’s early (C. reticulate) and mosambi (C. sinensis) infected with CBLVd from Sargodha, Pakistan. The results showed that chlorophyll contents were significantly lower in the diseased leaves samples of all the citrus cultivars as compared to healthy ones. Whereas, TSP was found in higher concentration in the CBLVd infected samples of citrus cultivars. Similarly, activities of PPO and PAL was increased significantly in leaves of citrus cultivars infected with CBLVd as compared to healthy. These findings were in confirmation that chlorophyll contents, enzymes and inhibitors were associated to response of plants towards pathogen infection. To the best of our knowledge, these biochemical alterations in host plants against CBLVd were studied for the first time not only in the Asian region but also in Pakistan. The results will lead to investigate the biochemical alterations in other citrus viroids infection.

Cellulolytic and xylanolytic enzyme combinations in the hydrolysis of red rice bran: A disparity in the release of nutraceuticals and its correlation with bioactivities

Multienzyme-aided processing is recommended as an effective method for releasing the bioactive compounds bounded to rice bran's cell wall matrix. This study aims to investigate the optimal cellulolytic-xylanolytic enzymes combination (CXC1 = 1.5 + 3 units, CXC2 = 3 + 2 units, CXC3 = 4.5 + 1 units per 2 g bran) for improving the release of nutraceuticals and bioactivities from red rice bran compared to control. The results showed significant (p ≤ 0.05) synergistic activities at CXC2 combination with the highest increase in ferulic acid (253%) in soluble phenolics, p-coumaric acid (66%) in bound phenolics and γ-oryzanol fractions (41%–743%). Bioactivity assays showed that all three enzyme combinations exhibited higher ferric reducing power (∼71%), DPPH• (∼13%), nitric oxide (∼114%) scavenging and inhibition of human LDL oxidation (∼13%–34%). While CXC1 and CXC2 increased superoxide anion (∼153%) and hydroxyl radical (∼44%) scavenging activities. Correlation study showed soluble phenolics, ferulic, caffeic acid and 24-methylenecycloartanyl ferulate, exhibiting positive correlation while protocatechuic acid and γ-tocopherol negative correlation with bioactivities. Thus, applying an optimal cellulolytic-xylanolytic enzyme combination is a potential approach for processing the rice bran into a functional food ingredient.

Exogenous application of moringa leaf extract improves growth, biochemical attributes, and productivity of late-sown quinoa.

Quinoa (Chenopodium quinoa Willd.) has gained significant popularity among agricultural scientists and farmers throughout the world due to its high nutritive value. It is cultivated under a range of soil and climatic conditions; however, late sowing adversely affects its productivity and yield due to shorter growth period. Inorganic and organic phyto-stimulants are promising for improving growth, development, and yield of field crops under stressful environments. Field experiments were conducted during crop cultivation seasons of 2016–17 and 2017–18, to explore the role of inorganic (hydrogen peroxide and ascorbic acid) and organic [moringa leaf extract (MLE) and sorghum water extract (sorgaab)] phyto-stimulants in improving growth and productivity of quinoa (cultivar UAF-Q7). Hydrogen peroxide at 100 μM, ascorbic acid at 500 μM, MLE at 3% and sorgaab at 3% were exogenously applied at anthesis stage of quinoa cultivated under normal (November 21st and 19th during 2016 and 2017) and late-sown (December 26th and 25th during 2016 and 2017) conditions. Application of inorganic and organic phyto-stimulants significantly improved biochemical, physiological, growth and yield attributes of quinoa under late sown conditions. The highest improvement in these traits was recorded for MLE. Application of MLE resulted in higher chlorophyll a and b contents, stomatal conductance, and sub-stomatal concentration of CO2 under normal and late-sowing. The highest improvement in soluble phenolics, anthocyanins, free amino acids and proline, and mineral elements in roots, shoot and grains were observed for MLE application. Growth attributes, including plant height, plant fresh weight and panicle length were significantly improved with MLE application as compared to the rest of the treatments. The highest 1000-grain weight and grain yield per plant were noted for MLE application under normal and late-sowing. These findings depict that MLE has extensive crop growth promoting potential through improving physiological and biochemical activities. Hence, MLE can be applied to improve growth and productivity of quinoa under normal and late-sown conditions.

Potential Role and Involvement of Antioxidants and Other Secondary Metabolites of Wheat in the Infection Process and Resistance to Fusarium spp.

This article provides a summary of current knowledge about wheat metabolites that may affect resistance against Fusarium head blight (FHB). The mechanisms of resistance, the roles of secondary metabolites in wheat defense, and future directions for breeding are assessed. The soluble phenols play an important role in redox regulation in plant tissues and can act as antimicrobial compounds. The color of cereal hulls and grains is caused by such natural pigments as anthocyanins in the aleurone, endosperm, and pericarp layers of the grain. Phenolic acids, alkylresorcinols, and phytohormones actively participate in the defense system, whereas carotenoids show various effects against Fusarium species that are positively correlated with the levels of their mycotoxins. Pathogen infestation of vegetative tissues induces volatile organic compounds production, which can provide defensive functions to infested wheat. The efficient use of native resistance in the wheat gene pool, introgression of resistant alleles, and implementation of modern genotypic strategies to increase levels of native secondary metabolites with antifungal properties can enhance the FHB resistance of new varieties. Expanding the breeding interest in the use of forms with different grain color and plant organs can be a potential benefit for the creation of lines with increased resistance to various stresses.

Antioxidant and anti-proliferative activity of free, conjugates and bound phenolic compounds from tomato and industrial tomato by-product.

The aim of this study was to evaluate the antioxidant and anti-proliferative activity of different fractions of phenolic compounds from tomato and tomato by-product. Soluble free phenolics and bound phenolics (BP) fractions from saladette tomato and industrial tomato by-product as well as, conjugated acid-hydrolysable phenolics (AHP) and alkaline-hydrolysable phenolics (AKHP) from saladette tomato, grape tomato and industrial tomato by-product, were tested. The scavenging effects of phenolic fractions on superoxide anion were determined using the PMS-NADH-NBT system. The myoglobin protection ratios of samples against hydroxyl radical were evaluated and the anti-proliferative effects in the MCF-7 breast cancer cell line were determined. AHP fraction from tomato by-product and AKHP fraction from grape and saladette tomato showed the highest inhibitory capacity of the superoxide anion (p ≤0.05). All samples had a myoglobin protection ratio from 30 to 50%. Regarding to cytotoxicity assays, all phenolic fractions from tomato by-product, as well as, BP, AHP, AKHP from saladette tomato and AHP from grape tomato showed important anti-proliferative activity against MCF-7 breast cancer cell line (IC50 <20μg/mL). From the results, we can conclude that tomato and tomato by-product are a good source of natural compound with important antioxidant and anti-proliferative activity.

Shiitake cultivation as biological preprocessing of lignocellulosic feedstocks – Substrate changes in crystallinity, syringyl/guaiacyl lignin and degradation-derived by-products

Formulation of substrates based on three hardwood species combined with modulation of nitrogen content by whey addition (0–2%) was investigated in an experiment designed in D-optimal model for their effects on biological preproceesing of lignocellulosic feedstock by shiitake mushroom (Lentinula edodes) cultivation. Nitrogen loading was shown a more significant role than wood species for both mushroom production and lignocellulose degradation. The fastest mycelial colonisation occurred with no nitrogen supplementation, but the highest mushroom yields were achieved when 1% whey was added. Low nitrogen content resulted in increased delignification and minimal glucan consumption. Delignification was correlated with degradation of syringyl lignin unit, as indicated by a significant reduction (41.5%) of the syringyl-to-guaiacyl ratio after cultivation. No significant changes in substrate crystallinity were observed. The formation of furan aldehydes and aliphatic acids was negligible during the pasteurisation and fungal cultivation, while the content of soluble phenolics increased up to seven-fold.

Bioconversion of lignin and methane production from Corn cobs (Zea mays) treated by lignin-degrading bacteria

Corn cobs are one of the potential feedstocks consisting of cellulose, hemicellulose and lignin, which provide potential lignocellulose biomass to be converted into renewable energy such as biogas through anaerobic digestion (AD). However, the recalcitrant structure of corn cobs lignocellulose makes it resistant to microbial access to the cell wall, and therefore the effective pre-treatment needs to be conducted. The biological pre-treatment using lignin-degrading bacteria is one of the promising bioconversion processes which will help to break down the lignocellulose structure. This study aims to analyse the ability of bacteria, Agrobacterium sp., Lysinibacillus sphaericus and Paenibacillus sp. in degrading lignin of corn cobs and therefore will enhance the methane released from AD. The ability of bacteria to degrade lignin was observed by analysis of total reducing sugar, total soluble phenols, lignin content, and weight loss, while the methane production was determined by the biochemical methane potential (BMP). The percentage of lignin content of untreated and pre-treated corn cobs with bacteria Agrobacterium sp., L. sphaericus and Paenibacillus sp. is 18.34%; 9.66%; 11.48% and 9.06%, respectively. The methane concentration (specific methane production) produced by using inoculum of Agrobacterium sp., L. sphaericus and Paenibacillus sp. with the addition of pre-treated corn cobs are 1.79%; 1.16% and 2.51%, respectively. These results were higher than the inoculum with the addition of untreated corn cobs.

Effect of the Fe-HBED chelate on the nutritional quality of tomato fruits

Despite active debate about Fe fortification of food due to Fe fertilization, not much is known about influence of Fe availability on fruit quality, including tomatoes. Thus, our goal was to study the effect of Fe-HBED chelate on the nutritional quality of tomato (Solanum lycopersicum L.) fruits. The results showed that supraoptimal Fe-HBED supplementation caused cultivar-dependent detrimental changes in elemental status of fruit pericarp. Following Fe supplementation significant increases in xanthophylls and β-carotene contents were recorded. The results showed that Fe supplementation did not strongly interfere with metabolism of amino acids and other secondary metabolites, as contents of free amino acids, lycopene, soluble phenolics and flavonoids were not significantly affected. Moreover, differences in further lycopene trafficking into different branches of secondary metabolism (biosynthesis of carotenoids and xanthophylls) were observed. The data point out the important impact of Fe supplementation on nutritional quality (elemental composition and content of carotenoids and xanthophylls) of tomato fruits and warn against usage of Fe-oversupplied soil or Fe-enriched water for cultivation of tomatoes.