Occurrence of Sphingomonas olei with elemental S oxidation capability in sodic soil: Potential role in sodicity reclamation and plant growth promotion.

The success of the sodic soil reclamation using elemental S (S°) depends on the population of the native S° oxidizers. Augmenting the native flora of the sodic soils with effective S° oxidizers can enhance the success of the sodic soil reclamation. Present study reports for the first time the S° oxidation potential of the Sphingomonas olei strain 20UP7 isolated from sodic soils with pHs 9.8 and ECe 3.6 dS m-1. Inoculation with S. olei strain 20UP7 caused 13.0-24.2 % increase in S° oxidation in different sodic soils (pHs 9.1-10.5). It improved the concentration of the Ca2+, Mg2+, PO43- and declined the HCO3- and total alkalinity of the soil solution. This isolate also showed appreciable P and Zn solubilization, indole acetic acid, ammonia, and titratable acidity production in the growth media. It tended to the formation of biofilm around sulphur particles. The PCR amplification with gene-specific primers showed the occurrence of soxA, soxB, and soxY genes with a single band corresponding to length of 850, 460, and 360 base pairs, respectively. The integration of the S. olei strain 20UP7 with S° caused 21.7-25.4 % increase in the rice and wheat yield compared to the soil treated with S° alone. This study concludes that the S. olei, native to high saline-sodic soils can be utilized for improving the sodicity reclamation and plant growth promotion using elemental S based formulations.

A hybrid machine learning algorithm for studying magnetized nanofluid flow containing gyrotactic microorganisms via a vertically inclined stretching surface.

The novelty of the present work is to acquire continuous functions as solutions rather than the discrete ones that traditional numerical methods generally produce and to minimize simulation times and higher computation costs that are the fundamental barriers to employing any numerical method. In this study, a novel hybrid finite element-based machine learning algorithm utilizing the Levenberg-Marquardt scheme with backpropagation in a neural network (LMBNN) is presented to analyze the nanofluid flow in the presence of magnetohydrodynamics and gyrotactic microorganisms through a vertically inclined stretching surface in a porous medium. Finite Element Method is used to generate the minimum reference dataset for LMBNN by varying six flow parameters in the form of six scenarios. Surface plots are utilized to understand how these scenarios affect velocity, temperature, concentration of nanoparticles, and density of motile microorganisms. Regression analysis, error histogram analysis, and fitness curves based on mean square error all support the LMBNN's effectiveness and dependability. Results reveal that temperature increases with the rise in Brownian motion and thermophoresis parameter, whereas the reverse trend has been noticed for Prandtl number. The motile microorganism density number decreases with the rise in Prandtl numbers but improves with the porosity parameter.

Characterization of flue gas desulphurized (FGD) gypsum of a coal-fired plant and its relevant risk of associated potential toxic elements in sodic soil reclamation.

Thermal Power Plant generates FGD gypsum as by-product during coal combustion. This study evaluates the characterization (spectroscopic and elemental), potentially toxic elements (PTEs) distribution, and environmental risk assessment of FGD gypsum for safe and sustainable use in agriculture. The XRD and SEM analysis confirmed the dominance of crystalline CaSO4·2H2O in FGD gypsum. The order of concentrations of PTEs in FGD gypsum was Fe > Al > Mn > Zn > Ni > Co. The residual fraction was the dominant pool, sharing 80-90% of the total PTEs. The heavy metals (HMs) were below the toxic range in the leachates. The Co, Ni, Al, Fe Mn, Zn had low (< 10%) risk assessment code and the ecotoxicity was in the range of 0.0-7.46%. The contamination factor was also low (0.0-0.16) at the normal recommended doses of FGD gypsum application for sodicity reclamation. The enrichment factor was in the order of Al < Mn < Co < Zn < Ni. Mn [enrichment factor (Ef) 1.2-2.0] and Co (Ef 1.7-2.8) showed negligible enrichment of metals, whereas Ni (Ef 4.3-5.2) and Zn (Ef 4.5-5.6) reported moderate accumulation in soil. The application of FGD gypsum @ 10 t ha-1 for sodicity reclamation will develop a geo-accumulation index below the critical values indicating its safe and sustainable use to achieve land degradation neutrality (LDN) and UN's Sustainable Development Goals.

Changes in soil microbial biomass and organic C pools improve the sustainability of perennial grass and legume system under organic nutrient management.

Introduction: The perennial grass-legume cropping system benefits soil because of its high biomass turnover, cover cropping nature, and different foraging behaviors. We investigated the response of soil organic carbon (SOC) pools and their stock to organic and inorganic nutrient management in the Guinea grass and legume (cowpea-Egyptian clover) cropping system. Methods: Depth-wise soil samples were collected after harvesting the Egyptian clover. Based on the ease of oxidation with chromic acid, different pools of SOC oxidizable using the Walkley-Black C method, very labile, labile, less labile, non-labile; and dissolved organic C (DOC), microbial biomass C (MBC), and total organic C (TOC) in soils were analyzed for computing several indices of SOC. Result and discussion: After 10 years of crop cycles, FYM and NPKF nutrient management recorded greater DOC, MBC, SOC stocks, and C sequestration than the NPK. Stocks of all SOC pools and carbon management index (CMI) decreased with soil depth. A significant improvement in CMI, stratification ratio, sensitivity indices, and sustainable yield index was observed under FYM and NPKF. This grass-legume intercropping system maintained a positive carbon balance sequestered at about 0.8Mg C ha-1 after 10 years without any external input. Approximately 44-51% of the applied carbon through manure was stabilized with SOC under this cropping system. The DOC, MBC, and SOC in passive pools were identified for predicting dry fodder yield. This study concludes that the application of organics in the perennial grass-legume inter cropping system can maintain long-term sustainability, enhance the C sequestration, and offset the carbon footprint of the farm enterprises.

Influence of tillage and residue management practices on productivity, sustainability, and soil biological properties of rice-barley cropping systems in indo-gangetic plain of India.

Introduction: Conservation agriculture is a sustainable system of farming that safeguard and conserves natural resources besides enhancing crop production. The biological properties of soil are the most sensitive indicator to assess the short term impact of management practices such as tillage and residue incorporation. Methods: Nine treatments of tillage and residue management practices [Reduced till direct seeded rice-zero till barley (RTDSR-ZTB); RTDSR-ZTB-green gram residue (Gg); Zero till direct seeded rice-zero till barley-zero till green gram (ZTDSR-ZTB-ZTGg); RTDSR-ZTB + rice residue at 4 t ha 1 (RTDSR-ZTBRR4); RTDSR-ZTBRR6; un-puddled transplanted rice (UPTR)-ZTB-Gg; UPTR-ZTBRR4; UPTR-ZTBRR6, and puddled transplanted rice (PTR)-RTB] executed under fixed plot for five years on crop productivity and soil biological properties under rice-barley production system. Results: The shifting in either RTDSR or ZTDSR resulted in yield penalty in rice compared to PTR. The PTR recorded highest pooled grain yield of 3.61 ha-1. The rice grain yield reduced about 10.6% under DSR as compared to PTR. The ZTB along with residue treatments exhibited significantly higher grain yield over ZTB, and the RTDSR-ZTBRR6 registered highest pooled grain yield of barley. The system productivity (12.45 t ha-1) and sustainable yield index (0.87) were highest under UPTR-ZTBRR6. Biological parameters including microbial biomass carbon, soil respiration, microbial enzymes (Alkaline phosphatase, nitrate reductase and peroxidase), fluorescein diacetate hydrolysis, ergosterol, glomalin related soil proteins, microbial population (bacteria, fungi and actinobacteria) were found to be significantly (p < 0.05) effected by different nutrient management practices. Based on the PCA analysis, Fluorescein diacetate hydrolysis, microbial biomass carbon, soil respiration, nitrate reductase and fungi population were the important soil biological parameters indicating soil quality and productivity in present experiment. The results concluded that UPTR-ZTBRR6 was a more suitable practice for maintaining system productivity and soil biological health. Discussion: The understanding of the impact of different tillage and residue management practices on productivity, soil biological properties and soil quality index under rice-barley cropping system will help in determining the combination of best conservation agriculture practices for improved soil quality and sustainable production.

The food-energy-water-carbon nexus of the rice-wheat production system in the western Indo-Gangetic Plain of India: An impact of irrigation system, conservational tillage and residue management.

The conventional rice-wheat system in the western Indo-Gangetic plain of India is energy and water intensive with high carbon footprint. The transition towards resource-efficient eco-friendly production technologies with lower footprint is required for inclusive ecological sustenance. A five-year (2016-17 to 2020-21) field experiment was conducted in RWS with hypothesis that pressurized irrigation systems [drip (DRIP) and mini-sprinkler (MSIS)] in conservation tillage [reduced (RT)/zero (ZT)] and crop residue management [incorporation (RI)/mulch (RM)] might result in higher resource use efficiency with lesser carbon footprint compared to conventional system. Experiment consisted five treatments namely (1) puddled transplanted rice followed by conventionally tilled wheat (PTR/CTW), (2) DRIP irrigated reduced till direct seeded rice (RTDSR) followed by zero-till wheat with 100 % rice residue mulching (ZTW + RM) (DRIP-RTDSR/ZTW + RM), (3) surface irrigated RTDSR followed by ZTW + RM (SIS-RTDSR/ZTW + RM), (4) MSIS irrigated RTDSR followed by ZTW + RM (MSIS-RTDSR/ZTW + RM), and (5) MSIS irrigated RTDSR with 1/3rd wheat residue incorporation followed by ZTW + RM (MSIS-RTDSR + RI/ZTW + RM). The pressurized irrigation system in RWS established under conservational tillage and residue management (DRIP-RTDSR/ZTW + RM and MSIS-DSR + RI/ZTW + RM) produced at par system productivity compared to PTR/CTW. Substantial nitrogen (79-114 ka ha-1) and irrigation water (536-680 mm) savings under pressurized irrigation systems resulted in 41-64 % higher partial factor productivity of nitrogen with 48-61 % lower water footprint. These systems had lower energy consumption attaining 15-21 % higher net energy, 44-61 % higher energy use efficiency, and 31-38 % lower specific energy. Efficient utilization of farm inputs caused lower greenhouse gas emission (39-44 %) and enhanced carbon sequestration (35-62 %) resulting 63-76 % lower carbon footprint over PTR/CTW. The information generated here might useful in developing policies for resource and climate-smart food production system aiming livelihood security and ecological sustainability in the region. Further, trials are needed for wider adaptability under different climate, soil and agronomic practices to develop site-specific climate smart practices.

Characterization and ecotoxicological risk assessment of sewage sludge from industrial and non-industrial cities.

The present study highlights the occurrence and the temporal variations of physicochemical properties, and heavy metals in the sludge from sewage treatment plants (STPs) located in industrial (two sites) and non-industrial (one site) cities of Haryana, India. The sludge was acidic (5.59) to neutral (7.21) with a mean EC of 7.4 dS m-1. Prominent heavy metals present in the sewage sludge from industrial sites were Cd, Ni, and Cr with maximum values of 2.83, 1449.0, and 3918.5 mg kg-1, respectively. The contamination and enrichment factor better explained the buildup of Ni, Cr, and Cu in the sewage sludge from industrial sites. The pH, total carbon, phosphorus, and other water-soluble anions, viz. SO42-, Cl-, HCO3-, and PO43-, were the most important attributes of sludge controlling the binding and removal of the metals with particulate matters during the phase separation in STPs. These attributes explained about 90% of the variation in Cd, Ni, Cr, Cu, Mn, and Zn content of the sludge from different STPs. Sludge from the non-industrial site had a low potential ecological risk index of 74.0 compared to a very high-risk index of 2186.5 associated with the industrial sites. This study concludes that besides the concentration of the heavy metals, the enrichment factor coupled with geo-accumulation or ecological risk index can effectively categorize the sludge. However, these indices need to be linked with bioaccumulation, bioaccessibility, and biomass quality under different agroecologies for guiding the safer use of sewage sludge in agriculture.

Integration of organics in nutrient management for rice-wheat system improves nitrogen use efficiency via favorable soil biological and electrochemical responses.

Introduction: The contrasting soil management in flooded-transplanted rice (Oryza sativa) and dry-tilled wheat (Triticum aestivum) poses a challenge for improving low nitrogen use efficiency (NUE) of the rice-wheat system. Integration of organics in nutrient management can bring in changes favoring efficient N uptake via changes in growing conditions and soil responses. Materials and methods: This study reported the results of a 15-year-long experiment on integrated nutrient management (INM) systems for rice-wheat cropping. The INM included substituting ~50% of chemical fertilizers via (i) including a legume crop (Vigna radiata) in the sequence and its biomass incorporation (LE), (ii) green manuring with Sesbania aculeata (GM), (iii) farmyard manure application (FYM), (iv) 1/3 wheat stubble in situ retention (WS), and (v) 1/3 rice stubble in situ retention. Results and Discussion: The INM strategies resulted in improved NUE compared to 100% chemical fertilizers (F). The INM had significantly higher net N mineralization and improved biological activity aligning with the NUE trends. The reductions in redox potential (Eh) and pH during rice season improved NUE under integrated management. Highly reduced conditions favored N mineralization and plant availability in form of NH 4 + - N resulting in enhanced uptake efficiency, in rice crop. The soil organic carbon (C) significantly increased in INM, and an effect of the active C fractions was evident on the NUE of the wheat crop. Conclusion: The results showed that these INM strategies can immensely benefit the rice-wheat system via improvement in biological health along with electrochemical changes for flooded rice, and labile-C-assisted improvement in soil conditions for wheat.

Whole genome sequence insight of two plant growth-promoting bacteria (B. subtilis BS87 and B. megaterium BM89) isolated and characterized from sugarcane rhizosphere depicting better crop yield potentiality.

Since sugarcane is a ratoon crop, genome analysis of plant growth-promoting bacteria that exist in its soil rhizosphere, can provide opportunity to better understand their characteristics and use of such bacteria in turn, may especially improve perennial crop productivity. In the present study, genome of two bacterial strains, one each of B. megaterium (BM89) and B. subtilis (BS87), isolated and reported earlier (Chandra et al., 2018), were sequenced and characterized. Though both strains have demonstrated plant growth promoting properties and enhanced in-vitro plant growth responses, functional annotation and analysis of genes indicated superiority of BS87 as it possessed more plant growth promotion attributable genes over BM89. Apart from some common genes, trehalose metabolism, glycine betaine production, peroxidases, super oxide dismutase, cold shock proteins and phenazine production associated genes were selectively identified in BS87 genome indicating better plant growth performances and survival potential under harsh environmental conditions. Genes for chitinase, d-cysteine desulfhydrase and γ-aminobutyric acid (GABA), as found in BM89, propose its selective utilization in defense and bio-control measures. Concomitant with better settlings' growth, scanning electron micrographs indicated these isolated and characterized bacteria exhibiting healthy colonization within root of sugarcane crop. Kegg pathways' assignment also revealed added pathways namely carbohydrate and amino acid metabolism attached to B. subtilis strain BS87, a preferable candidate for bio-fertilizer and its utilization to promote growth of both plant and ratoon crops of sugarcane usually experiencing harsh environmental conditions.

Bio-functional properties of probiotic Lactobacillus: current applications and research perspectives.

Lactic acid bacteria as a starter culture are very important component in the fermentation process of dairy and food industry. Application of lactic acid bacteria as probiotic bacteria adds more functionality to the developed product. Gut colonizing bacteria have attractive benefits related to human health. Bio-functional properties such as antimicrobial activity, anti-inflammatory, ACE-inhibitory, antioxidant, antidiarrheal, antiviral, immunomodulatory, hypocholesterolemic, anti-diabetic and anti-cancer activities are the most applicable research areas of lactic acid bacteria. Different strains of Lactobacillus are generally consumed as probiotics and colonize the gastrointestinal tract. Sometimes these bacteria may possess antimicrobial activity and may positively influence the effect of antibiotics. Use of Lactobacillus spp. for the development of functional foods is one of the promising areas of current research and applications. Individual bacterial species have unique biological activity, which may vary from strains to strains and identification of this uniqueness could be helpful in the development of functional and therapeutic food products.

Antioxidant compounds from microbial sources: A review.

Free radicals are one or more unpaired electrons containing reactive molecules, which can damage nucleic acids, proteins, carbohydrates, and lipids, leading to several diseases including early aging, cancer and atherosclerosis. Antioxidants can scavenge these free radicals to prevent cellular damage by ultimately reducing the oxidative stress and thus have a beneficial effect on human health. Epidemiological studies have already revealed that higher intake of antioxidants as food supplements results in reduced risk of many diseases. Exploring natural antioxidants and its role in human health & nutrition is an emerging field. Several biological sources like medicinal plants, vegetables, spices and fruits have been evaluated as sources of potentially safe natural antioxidants. Beside plants, microorganisms are the potential source of novel bioactive compounds to be used in medical, agricultural, and industrial sectors. As compared to plants, microbes can be grown under controlled conditions at a faster rate, which make them a potential source of natural bioactive molecules for food and nutraceutical applications. This review summarizes the potential of different microorganisms including actinomycetes, bacteria, blue green algae, fungi, lichens and mushrooms to be explored as the source of such bioactive compounds.

Antioxidant Potential and Extracellular Auxin Production by White Rot Fungi.

Selective lignin degrading white rot fungi viz. Phanerochaete chrysosporium, Phlebia brevispora, and Phlebia floridensis were selected to evaluate antioxidant potential and auxin (indole acetic acid) production in complex and synthetic medium. Antioxidant potential of these fungi was tested against different free radicals including 2, 2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide, ferrous ion, and ferric ion along with total phenolic content. All the fungal strains produce phenolics ranging from 5.2 to 16.7 mg/ml and demonstrated various free radical and metal ion scavenging activity. Growth medium significantly affected all the activities. Almost similar antioxidant activity (~ 72% DPPH scavenging activity) was demonstrated by all the fungi in yeast extract glucose medium; however, the activity was lower in Czapek dox's medium (from 60 to 45%). Indole acetic acid production was maximum in P. brevispora (31 µg/ml), which was closely followed by P. chrysosporium and P. floridensis. The extracts did not show any mutagenic or cytotoxic effect. Thus, these white rot fungi highlight their significance as a new source for the prompt production of extracellular antioxidants and auxin.

Biochemical Investigation of Tissue Oxidative Stress and Angiogenesis with Associated Trace Elements in Breast Disease Patients in Uttarakhand, India.

Breast cancer is a heterogeneous cancer with diverse clinical symptoms and an ambiguous molecular spectrum. Oxidative damage, antioxidant activity, and angiogenesis combine to form significant complex factors that stimulate breast cancer development and progression. This study is designed to determine level changes in total antioxidant status and markers of lipid peroxidation melondialdehyde (MDA) and angiogenesis vascular endothelial growth factor (VEGF) along with related micronutrients of copper, zinc, magnesium, and iron in malignant and benign breast disease tissue extracts. We assess specificity and sensitivity of those markers using the area under the curve of receiver operator characteristic (ROC) curve analysis. Association studies are done with correlation analysis. The tissue extract level of MDA markers is found to be significantly higher (14.118 ± 1.47 nmol/g tissue; p < 0.05), with significantly depleted levels of antioxidants (5.983 ± 1.661 nmol/g tissue; p < 0.05). The tissue VEGF level also significantly increases in a diseased condition (512.466 ± 5.661 pg/mg tissue) versus the nondiseased condition (422.433 ± 13.615 pg/mg tissue). Related trace-element levels show a significant mixed pattern among studied groups. VEGF emerges as the best discriminatory biomarker of breast cancer presence, in accordance with ROC analysis. Oxidative stress and angiogenesis are found to be important factors in breast cancer development. This study forms the basis for future studies that focus on the relationship between roles of indices studied and cancer induction.

Comparative evaluation of the effect of chlorhexidine and Aloe barbadensis Miller (Aloe vera) on dentin stabilization using shear bond testing.

INTRODUCTION: The main objective of adhesive dentistry is to create an effective, durable union between the tooth structure and restorative material. However, degradation of adhesive dentine interface remains largely responsible for the relatively short lifetime of tooth colored resin restoration. AIM: The aim of the study is to compare the dentin collagen stabilization property of Chlorhexidine (CHX) and Aloe barbadensis Miller using shear bond strength testing. MATERIALS AND METHODS: Occlusal reduction was done in sixty extracted human mandibular molars to expose the mid coronal dentin and divided into three groups n = 20. Following the surface pretreatment (Group 1 = control, Group 2 = CHX, Group 3 = Aloevera), dentine bonding agent and composite resin were applied and cured. The specimens were then subjected to shear bond strength testing. RESULTS: From the results analyzed, it was noted that there was statistically significant difference between the groups Control and CHX and Control and A. barbadensis Miller (P < 0.05), specifically the values of Control < CHX and Control < A. barbadensis Miller (P < 0.05). However, there was no statistically significant difference between CHX and A. barbadensis Miller (P > 0.05). Hence, the following result for the shear bond strengths to dentin was obtained: Control < CHX ≈ A. barbadensis Miller. CONCLUSION: CHX and A. barbadensis Miller, as pretreatment agents of acid demineralized dentin collagen, has no adverse effect on the immediate shear bond strength of a two-step etch and rinse adhesive to dentin.

Evaluation of metal contamination and phytoremediation potential of aquatic macrophytes of East Kolkata Wetlands, India.

OBJECTIVES: The present study analyzes metal contamination in sediment of the East Kolkata Wetlands, a Ramsar site, which is receiving a huge amount of domestic and industrial wastewater from surrounding areas. The subsequent uptake and accumulation of metals in different macrophytes are also examined in regard to their phytoremediation potential. METHODS: Metals like cadmium (Cd), copper (Cu), manganese (Mn), and lead (Pb) were estimated in sediment, water and different parts of the macrophytes Colocasia esculenta and Scirpus articulatus. RESULTS: The concentration of metals in sediment were, from highest to lowest, Mn (205.0±65.5 mg/kg)>Cu (29.9±10.2 mg/kg)>Pb (22.7±10.3 mg/kg)>Cd (3.7±2.2 mg/kg). The phytoaccumulation tendency of these metals showed similar trends in both native aquatic macrophyte species. The rate of accumulation of metals in roots was higher than in shoots. There were strong positive correlations (p<0.001) between soil organic carbon (OC) percentage and Mn (r =0.771), and sediment OC percentage and Pb (r=0.832). Cation exchange capacity (CEC) also showed a positive correlation (p<0.001) with Cu (r=0.721), Mn (r=0.713), and Pb (r=0.788), while correlations between sediment OC percentage and Cu (r=0.628), sediment OC percentage and Cd (r=0.559), and CEC and Cd (r=0.625) were significant at the p<0.05 level. CONCLUSIONS: Bioaccumulation factor and translocation factors of these two plants revealed that S. articulatus was comparatively more efficient for phytoremediation, whereas phytostabilization potential was higher in C. esculenta.

Influence of cervical preflaring using different rotary instruments on the accuracy of apical file size determination: A comparative in-vitro study.

AIM: To investigate the influence of cervical preflaring using different rotary instruments on apical file size determination. MATERIALS AND METHODS: Extracted human molar teeth were randomly divided in to eight groups (N = 10): Control group (CG); LA Axxess group (LA); HyFLex group (HF); GatesGlidden group (GG); ProTaper group (PT); Race group(RC); FlexMaster group (FM); and K3 group (K3). Patency was maintained and working length was established under magnification. All instruments were used according to manufacturer's instructions. Steriomicroscopic images were taken to determine the discrepancies in diameters. ProPlus software (USA) was used to determine the diameter of the root canal. ANOVA test and Post Hoc Tests-Bonferroni Multiple Comparisons were used for statistical analysis. RESULTS: Canals preflared with LA Axxess burs showed the best results. Control group that is, the canals with no cervical preflaring showed the maximum discrepancy between the initial apical file diameter and apical canal diameter. CONCLUSION: Cervical preflaring plays an important role in reducing the discrepancy between initial apical file diameter and apical canal diameter.

Optimization of Antioxidant Potential of Penicillium granulatum Bainier by Statistical Approaches.

A three-step optimization strategy which includes one-factor-at-a-time classical method and different statistical approaches (Plackett-Burman design and response surface methodology) that were applied to optimize the antioxidant potential of Penicillium granulatum. Antioxidant activity was assayed by different procedures and compared with total phenolic content. Primarily, different carbon and nitrogen sources were screened by classical methods, which revealed sucrose and NaNO3 to be the most suitable. In second step, Plackett-Burman design also supported sucrose and NaNO3 to be the most significant. In third step, response surface analysis showed 4.5% sucrose, 0.1% NaNO3, and incubation temperature of 25°C to be the optimal conditions. Under these conditions, the antioxidant potential assayed through different procedures was 78.2%, 70.1%, and 78.9% scavenging effect for DPPH radical, ferrous ion, and nitric oxide ion, respectively. The reducing power showed an absorbance of 1.6 with 68.5% activity for FRAP assay.

Antioxidant Activity of Aspergillus fumigatus.

The antioxidant activity of Aspergillus fumigatus was assayed by different procedures and correlated with its extracellular total phenolic contents. Different physio-chemical parameters were optimized to enhance the activity. The culture grown under stationary conditions for 10 days at 25°C at pH 7 gave the best antioxidant activity. Statistical approaches demonstrated sucrose and NaNO(3) to be the most suitable carbon and nitrogen sources, respectively. Response surface analysis showed 5% sucrose, 0.05% NaNO(3), and incubation temperature of 35°C to be the optimal conditions for best expression of antioxidant activity. Under these conditions, the antioxidant potential assayed through different procedures was 89.8%, 70.1%, and 70.2% scavenging effect for DPPH radical, ferrous ion and nitric oxide ion, respectively. The reducing power showed an absorbance of 1.0 and FRAP assay revealed the activity of 60.5%. Extracellular total phenolic content and antioxidant activity as assayed by different procedures positively correlated.

In vitro antioxidant potential of some soil fungi: screening of functional compounds and their purification from Penicillium citrinum.

Fungal isolates (Aspergillus wentii 1, A. wentii 2, Penicillium citrinum, Penicillium granulatum) were selected to study their in vitro antioxidant potential by various assay procedures. Czapek-Dox's medium was selected for the growth of fungi as it supported the best antioxidant activity based on their EC(50) values, P. citrinum was the best followed by P. granulatum, A. wentii 1, and A. wentii 2. The chromatographic analyses showed several compounds possessing antioxidant activity in the fungal extracts. Two such compounds were partially purified from P. citrinum which demonstrated potent antioxidant activity, equally effective or better than some of the standard antioxidants.