Total Microbial Activity Research Articles

Evaluation of minced beef quality fortified with some edible microalgae species during cryogenic storage

The aim of this study is to evaluate the effect of some microalgae species adding with different forms on minced beef meat shelf life during cryogenic storage for 13 days. Chlorella vulgaris and Arthrospira platensis are chosen because of their safety and high nutritional value. Microalgae nanoparticles with their different forms have been prepared by using emulsification solvent evaporation method. Thiobarbituric acid (TBA), total volatile nitrogen (TVN) and microbial growth activity as spoilage indicator were evaluated. The results recorded the highest antioxidants content related to 147.03 mg gallic acid/D.W. extract total phenolics and 186.8 µg quercetin/ D.W. extract total flavonoids for C. vulgaris nano-form extract (S8) and A. platensis nano-form extract (S6), respectively. Lowest content of TBA and TVN for samples of S8, S6, C. vulgaris nano-form powder (S7) and A. platensis nano-form powder (S5) were (0.81 and 17.80), (0.86 and 18.20), (0.92 and 18.90) and (0.98 mg/kg and 18.6 mg/100 g), respectively at end of the storage period. The metabolites based on gas chromatography-mass spectrometry were determined for S4, S6, and S8. The extract of C. vulgaris and its nano-form is rich in the oxygenated compounds, representing 87.37 and 89.88 %, respectively. The study illustrated that using of the nanotechnology for powder and extract microalgae species extends the minced beef meat shelf life during cryopreservation for 13 days at 4 °C ± 1.

Bio-transformation of poultry litter and activated sewage sludge to produce biomixtures for the remediation of water polluted with pesticides

The aim of this study was to formulate novel biomixtures with the ability to dissipate globally used pesticides. For this, an effective stabilization of two wastes, poultry litter and activated sewage sludge, was achieved through a combination of composting and vermicomposting, with the aid of the earthworm Eisenia fetida. Hence, two different mixtures were prepared combining the wastes with and without the addition of sewage sludge, and their physicochemical and microbiological characterization was examined during both processes. Earthworms reproduction was promoted by more than fourteen times the initial number of individuals introduced. This step made it possible to obtain substrates rich in organic matter, stable and non-pathogenic. The resulting vermicomposted substrates (V–C1 and V–C2) were used to produce two different biomixtures with wheat stubble (WS) and soil (S): SWSV-C1 and SWSV-C2, and they were tested for the remediation of a solution of five pesticides (2,4-D, cypermethrin, imidacloprid, acetochlor and dimethoate) in a 119-days assay. Comparisons were made with a WS-only biomixture (SWS) and a soil control. All biomixtures were more successful in dissipating the pesticides than soil; 2,4-D, dimethoate, and acetochlor degradation reached more than 99% in the three biomixtures after 28–56 days of assay. Biomixtures containing either vermicomposts acted faster than SWS, particularly for 2,4-D, dimethoate and cypermethrin. The total microbial activity was found to be higher in the two biomixtures containing vermicompost, which can be linked to their enhanced performance in the degradation of pesticides. Although the germination of Lactuca sativa proved that neither of the three spent biomixtures were phytotoxic at the end (germination index >60%), only SWSV-C1 and SWSV-C2 proved to be safe for the survival of E. fetida. This work confirms that vermicompost improves the success of biomixtures, not only in terms of pesticide removal, but also providing non-toxic spent biomixtures.

Evaluation of Organic Manure Amendments on Soil Carbon Saturation Deficit in a Rainfed Agriculture System of Himalaya, India

ABSTRACT Organic manure amendments into the rainfed agricultural soil could change the carbon saturation deficit. This study was conducted in the central Himalayan region of India to assess the impact of varying quantities of farmyard manure (FYM) and vermicompost (VC) on changes of soil carbon saturation deficit in the rainfed agricultural system. The experimental plots with three replications and three different amendment rates, such as 15, 30, and 60 Mg ha−1 of FYM and VC were used on the traditional paddy-wheat-finger millet-fallow cropping system. The soil amended with FYM and VC showed significant (p < .05) variations in the soil carbon content, nitrogen content, total microbial activity, β-glucosidase activity, and acid phosphatase activity with an increasing rate of both the manures in each cropping season. The mean soil carbon saturation deficit values varied from 25 to 36% and 19 to 28% in the first year cropping and second year cropping seasons, respectively. Our results demonstrate that the VC amendment was better than FYM for the accumulation of more carbon content in the rainfed agricultural soils of Himalaya, whereas the organic manure amendment rates must be considered for climate change impact mitigation action policy in the future.

Microbial fuel cells with polychlorinated biphenyls contaminated soil as electrolyte: energy performance and decontamination potential in presence of compost

The electrical performance of Terrestrial Microbial Fuel Cells (TMFCs) with soil as the electrolyte was tested with two concentrations (150 or 250 ng/g soil) of PCBs (Polychlorinated biphenlys) and compost (3 % w/w) in an experiment lasting 60–80 days. Energy output levels were recorded daily by varying the external resistance for detecting the best operating conditions. PCB concentrations and microbiological analyses (total microbial abundance and activity) were performed at the start and end of the experiment. The highest power generation (207 ± 80 mW/m2 at 112.5 Ω) was recorded in the presence of compost with the lowest PCB concentration, when compared to TMFCs without compost (1.5 ± 0.2 mW/m2 at 300.8 Ω). The results demonstrated that the power generation was correlated with a lower internal resistance and a higher microbial activity. Moreover, chemical results indicated a possible threshold of PCB concentration for the concurrently electricity production and PCB degradation. In fact, PCB removal was obtained only in the cells with high PCB concentration, achieving a reduction of 21 % and 16 % with and without compost, respectively. The microbiological results showed that an additional organic carbon source (methanol or compost) promoted microbial activity and abundance. A positive correlation was found between microbial activity and TMFC electrical output only in the case of PCB low concentration, in the presence of compost. No previous studies addressed the performance of TMFCs with different levels of PCBs in terms of soil decontamination and electricity production. Although a longer experiment is needed, considering PCB persistence in soils, this experiment provided useful information and a new insight on the TMFC effectiveness for soil decontamination and electricity production. The results presented here support considerations about soil resilience through microbial communities and orient further research on contaminant degradation by TMFCs.

Non-invasive measurement of spoilage of packed fish using halochromic sensor

Purpose This study aims to develop a pH-functional thin-film sensor for non-invasive measurement of spoilage of packed fish. Design/methodology/approach At first, polymers of natural origin such as hydroxy(propyl)methyl cellulose, potato dextrose agar and starch alongside a pH sensitive-mixed indicator formulation were used to produce thin film sensor. The developed thin film sensor was tested for monitoring the spoilage of seafood stored at 4°C. Using ultraviolet-visible and Fourier-transform infrared spectroscopy, the halochromic sensor was characterised. In addition, the halochromic response of the thin film was directly correlated to the total volatile base nitrogen emitted by the packaged fish, pH, microbial activity and sensory evaluation. Findings The results suggested the developed biopolymer-based thin film sensor showed different colours in line with the spoilage of the packed fish, which could be well correlated with the total volatile base nitrogen, microbial activity and sensory evaluation. In addition, the thin film sensors exhibited a high degree of biodegradability. The biopolymers-based thin film halochromic sensor has exhibited excellent biodegradability along with sensitiveness towards the spoilage of the packed fish. Originality/value In the future, consumers and retailers may prefer seafood containers equipped with such halochromic sensors to determine the degree of food deterioration as a direct indicator of food quality.

Potential valorization and transformation of plastic biomass waste into useful fertilizers in agricultural Mediterranean soils under extreme climate conditions

Plastics are widely used in agricultural practices, although recently they have been recognized as a new emerging risk in soils. Polyethylene (PE), is commonly used by farmers to cover agricultural practices; geotextile, is used mainly for ground and crop covering; and polyvinyl chloride (PVC) is considered the main material contained in irrigation hoses. The present study aimed to assess the effects of three plastics (polyethylene, geotextile, polyvinyl chloride) on the soils’ fertility. Several pot experiments were conducted in soil samples from the study area (Thessaly) contaminated with adequate amounts of each plastic type (PE, geotextile: 2% v/v and PVC: 5% v/v). Water was added in two quantities: one to maintain typical soil moisture levels according to the crops’ requirements and an elevated amount to form supersaturating soil conditions similar to those following a flood event. Furthermore, temperature effect was also investigated to assess its impact on plastics’ behavior and soil fertility. The levels of all nitrogen forms and the microbial activity were determined at 10, 30, and 60 days. Significant changes were observed in the concentrations of nitrate, nitrite, and ammonium ions under ambient soil moisture conditions especially when the microplastics were incubated for a longer period. PE addition resulted in greater changes, followed by geotextile, although PVC addition did not induce significant changes in the nitrification process during the experimental time. PE and geotextile microplastics appeared to enhance microbial colonization and total microbial activity. In addition, soil characteristics were notably altered when moisture stress conditions were reached (85%) and when soils were flooded for two months, leading to a severe decrease in the availability of all nitrogen forms. The results showed that alterations in soil nitrogen forms in the presence of plastics study are crucial for maintaining the health and improving the productivity of Mediterranean soils.

Medium-term interactive effects of herbivores and plant life form on the biochemistry of shallow sandy soils in a protected semi-arid savanna

Savannas are characterized by the co-occurrence of two different plant life forms: grasses and trees. Herbivory plays a major role in the balance between grasses and trees in savanna ecosystems. The present study aimed to investigate the impact and interactions between long-term (i.e. 20 years) herbivory and/or its exclusion and plant life form on the soil biochemistry of a protected semi-arid savanna ecosystem in the Kruger National Park (KNP), South Africa. To study the effects of herbivory on soil properties, herbivore exclosures (fully fenced areas, partially fenced areas, and an unfenced area) were used in conjunction with plant life form (trees and grasses) were considered. Interaction effects of herbivory and plant life form on soil pH, electrical conductivity (EC), total nitrogen (TN), total carbon (TC), available phosphorus (available P), exchangeable cations (K+, Na+, Mg2+ and Ca2+) cation exchange capacity (CEC), organic matter (OM) and total microbial activity were determined on savanna soils in the Nkuhlu exclosures, KNP. Exclosures where herbivores were present had significantly higher soil pH, The presence of herbivores caused an increase in soil pH, EC, exchangeable Na, CEC, and OM. The influence of the tree canopy was significantly more pronounced in elevating total C and N, exchangeable K+, Mg2+ and Ca2+, CEC and OM than observed in the open grassland zones across all exclosures. The two-way interaction between herbivory and plant life form resulted in significant decreases in TN, TC, exchangeable K, Na and Mg in open grassland areas outside of herbivore exclosures where large animals had direct access, as compared to areas within the exclosures which was protected from animal entry herbivory. This data can be used by national parks as an indicator to increase their knowledge of environmental issues relating to maintaining and preserving landscape features of savannas.

Peach (Prunus persica L. Batsch) perfection: Boosting yields with mulching

The present study aimed to investigate the effects of various mulching strategies on the growth and yield of peach crops, as well as on soil hydrothermal regimes, weed infestation, and microbial properties. A field experiment was conducted, implementing various organic residue mulches including locally available grass and pine needle mulch, as well as inorganic mulches such as black and transparent mulch, control treatment comprising blanket recommendation. Results indicated that plots with black polythene mulch showed the highest fruit productivity, fruit yield, fruit length and diameter. Furthermore, black mulch and mulch mat treatments demonstrated complete weed control efficiency. Weed species Anagalis arvensis showed the highest maximum frequency, density, relative frequency, and relative density, while Biden pilosa had the highest abundance and relative abundance. The study also found that the impact of grass and pine mulch was of interest, as it helped regulate soil hydrothermal regimes and significantly enhanced total viable count, microbial activity, and microbial biomass carbon. In conclusion, these findings emphasize the potential of mulching techniques to improve peach crop yield and soil health.

Application of iron oxides modified volcanic rock in continuous phenol wastewater anaerobic treatment: Performance and underlying mechanisms

In this study, volcanic rocks (VR) or iron oxides modified volcanic rocks (IOVR) were added into the upflow anaerobic sludge bed reactor to serve as the supporting materials for improving phenol containing wastewater treatment efficiency. Results showed that with the presence of supporting materials the anaerobic digestion efficiency was effectively improved. In stage Ⅳ, in VR reactor and IOVR reactor the organics removal efficiency were 97.5% and 120.0% higher than that in control reactor, and the methane production were 71.2% and 105.3% higher than that in control reactor, respectively. Mechanisms exploration indicated that the activity of the electron transport system (ETS) and Coenzyme F420 were obviously improved in both VR reactor and IOVR reactor, which played an important role in organics decomposition and methanogenesis process, respectively. Microbial community analysis indicated that the frequency of functional genomes encoding key enzymes was effectively improved with the existence of supporting materials, especially in IOVR reactor, which meant the total microbial activity was significantly enhanced. Besides, the abundance of syntrophic bacteria (i.e. Clostridium and Longilinea) and syntrophic archaea (i.e. Methanothrix and Methanobacterium) also increased in these two reactors, which meant that syntrophic metabolism was potentially established and played an important role during anaerobic digestion.

Soil invertebrate and microbial activity rehabilitation by compost application after road construction and volcanic disturbance

Topsoil and plants had been removed for the construction of the “De los Siete Lagos” road when the June 2011 Puyehue–Cordón Caulle Complex volcanic eruption deposited 30 cm of tephra. Our objective was to study the active rehabilitation of substrate on roadsides simultaneously affected by road construction and volcanic eruption by compost addition. We studied two biological communities frequently forgotten by rehabilitation measures: invertebrates (density, richness) and microorganisms (enzymatic activities); both in the surface organic matter created by compost addition and the tephra substrate. In December 2012, we installed control, biosolids compost (BC) and municipal waste compost (MC) plots on roadside exclosures. Forest reference sites were also studied. Samplings were performed in spring 2013 and summer 2014. No surface organic matter was found in control plots, and no invertebrates were detected in the tephra layer of control plots in both samplings. BC and MC promoted the formation of a surface organic matter layer that harbored invertebrate and enzymatic activity in both sampling seasons. There were no significant differences in invertebrate density among BC, MC, and forest both in the surface organic matter and the tephra substrate. However, BC and MC invertebrate communities, dominated by springtails, did not resemble the forest community, where oribatids were the most common taxa. Statistically significant differences in total (surface organic matter + tephra substrate) microbial activities indicated a treatment order of forest &gt; BC ≥ MC &gt; control for enzymes related with the mineralization of nitrogen (leucine‐aminopeptidase) and phosphorus (acid phosphomonoesterase).

The effects of Cyclina sinensis bioturbation on alkaline phosphatase (APA) and total microbial hydrolytic activities (MBA) in marine clam-shrimp integrated ponds.

This study investigated the influence of Venus clam Cyclina sinensis bioturbation activities on the total benthic microbial and phosphatase activities and selected sediment properties: total phosphorous TP, total organic nitrogen-TON and total organic carbon-TOC. Sediments samples from clam-shrimp integrated-pond and non-clam integrated-pond were sampled for the study in which microbial activity (MBA) and alkaline phosphatase activity (APA), sediment organic contents: TP, TON, TOC, TOM and water quality parameter (dissolved oxygen, temperature, pH and moisture content were analyzed. The p-nitrophenyl phosphate disodium (p-NPP) and Fluorescein diacetate-(FDA) were adopted to measure APA and MBA respectively. Results indicated that microbial activity-MBA and alkaline-phosphatase activity-APA in sediments significantly increased in the pond cultured with clam/shrimp compared to non-clam cultured pond. Phosphate concentration increased significantly and varied among months (p<0.05) implying increased nitrogen concentration in the sediments. The concentrations of total organic nitrogen and total organic carbon didn't differ significantly among months and with the treatments (p>0.05), implying increased TON mineralization. Correlation analyses showed that there was positive correlation with the total microbial activity, alkaline-phosphatase activity, phosphorous concentration and organic matter content within the sediments bioturbated by the Venus clam. The results suggest that, the Venus clam sediment reworking mechanisms in sediment influenced the sediment microbial and APA activities and mineralization thereby affecting the pond alkaline phosphatase enzyme related activities.

Re-Thinking Table Salt Reduction in Bread with Halophyte Plant Solutions

Sodium intake higher than it is physiologically necessary has been associated with some non-communicable diseases such as hypertension, cardiovascular disease, and stroke. Bread is commonly consumed and is a major source of sodium in the human diet. Among the interventions to reduce the salt content in bread, the incorporation of salty taste halophyte powder could be a promising strategy. In the present work, Sarcocornia perennis was incorporated as a food ingredient to substitute the salt (sodium) of white wheat bread (1.2% NaCl/0.47% sodium, flour basis). Powdered dried S. perennis was incorporated into bread by replacing the same amount of sodium (0.47%, flour basis) and half of the sodium concentration (0.235%, flour basis), respectively, B100 and B50 bread samples. The bread samples were analyzed to evaluate the impact of the sodium chloride replacement by S. perennis powder on total baking loss, specific volume, crumb color, textural properties, microbial activity, nutritional and mineral composition and sensory evaluation. The incorporation of S. perennis increased the specific volume but had no relevant impact on the textural properties of bread. Furthermore, the substitution of sodium chloride by S. perennis powder allowed a more colored (greenish and yellowish) and dark crumb leading to a lower whiteness index. Compared with control bread, the addition of S. perennis powder promoted a significant increase of all bread’s nutrients and minerals, namely calcium, phosphor, iron, and manganese. Besides the improvement of bread quality, B100, and B50 bread samples were both sensorily well accepted and with similar scores to all the evaluated sensorial attributes. Moreover, the reduction of sodium to half (0.235% sodium (flour basis) in bread (B50) did not affect the acceptability of tasters, as compared with B100 (0.47% sodium (flour basis)). Both new bread formulation has microbiological quality as ready-to-eat product. However, taking into account greater stability over time for microbial spoilage, mainly caused by fungi and yeasts, B50 bread is more promising. The B50 bread sample is also a potential strategy to obtain a sodium reduction of 50% in bread, which could be essential to reduce the overall sodium daily intake and bring important economic and public health benefits.

Low Heating Effects on The Total Microbial Activity and Physico-Chemical Properties of Stingless Bee (Heterotrigona itama) Honey

The high moisture content of stingless bee honey (SBH) is a worrisome problem and heat treatment is used to reduce the moisture and maintain the honey’s quality by destroying the microorganisms that affect the physico-chemical properties of honey during storage. Low heat treatment (45 °C) for 0, 30, 60, 90, and 120 min were conducted to determine the total microbial activity using fluorescein diacetate hydrolysis (FDA). The total microbial population that subsequently affected the physico-chemical properties was also analyzed. The total microbial activities of SBH were significantly reduced after thermal treatment at 45 °C for 90 min (63.76 µg FDA/g/h) and 120 min (62.43 µg FDA/g/h) compared with control (67.127 µg FDA/g/h). Also, the moisture content, electrical conductivity (EC), pH, and free acidity of the heat-treated SBH at all durations were significantly reduced compared with the control. The total microbial activity was detected as significantly correlated to bacterial and fungal populations, moisture content, EC, pH, and free acidity of low heat-treated SBH. Low heat treatment at 45 °C for 120 min was efficient to reduce the total microbial activity, and total acidity, and increasing the pH of SBH. Prolonging the heating duration is suggested to further reduce the water content, and total microbial activity and further increase the shelf life of SBH.

Growth of grasses and forbs, nutrient concentration, and microbial activity in soil treated with microbeads

Microplastics have emerged as an important threat to terrestrial ecosystems. To date, little research has been conducted on investigating the effects of microplastics on ecosystem functions and multifunctionality. In this study, we conducted the pot experiments containing five plant communities consisting of Phragmites australis, Cynanchum chinense, Setaria viridis, Glycine soja, Artemisia capillaris, Suaeda glauca, and Limonium sinense and added polyethylene (PE) and polystyrene (PS) microbeads to the soil (contained a mixture of 1.5 kg loam and 3 kg sand) at two concentrations of 0.15 g/kg (lower concentration, hereinafter referred to as PE-L and PS-L) and 0.5 g/kg (higher concentration, hereinafter referred to as PE-H and PS-H) to explore the effects of microplastics on total plant biomass, microbial activity, nutrient supply, and multifunctionality. The results showed that PS-L significantly decreased the total plant biomass (p = 0.034), primarily by inhibiting the growth of the roots. β-glucosaminidase decreased with PS-L, PS-H, and PE-L (p < 0.001) while the phosphatase was noticeably augmented (p < 0.001). The observation suggests that the microplastics diminished the nitrogen requirements and increased the phosphorus requirements of the microbes. The decrease in β-glucosaminidase diminished ammonium content (p < 0.001). Moreover, PS-L, PS-H, and PE-H reduced the soil total nitrogen content (p < 0.001), and only PS-H considerably reduced the soil total phosphorus content (p < 0.001), affecting the ratio of N/P markedly (p = 0.024).Of interest, the impacts of microplastics on total plant biomass, β-glucosaminidase, phosphatase, and ammonium content did not become larger at the higher concentration, and it is observable that microplastics conspicuously depressed the ecosystem multifunctionality, as microplastics depreciated single functions such as total plant biomass, β-glucosaminidase, and nutrient supply. In perspective, measures to counteract this new pollutant and eliminate its impact on ecosystem functions and multifunctionality are necessary.

Effect of cereal-legume intercrops on the soil enzymatic activity

Sowing and harvesting cereals with legumes is an old crop production practice. The main goal of cultivation is to make the best use of the area and to increase the quality and yield of the crops. The intercropping of cereals and legumes can stimulate the biological activity of the soil, thus increasing the recycling of soil organic matter. Competition between two or more plants has a positive effect on the nitrogen fixation of legumes. In organic form the soil enzyme activity increasing is more effective which is provided by the winter pea (Pisum sativum L.) in this crop production system. We set up our experiment at the experimental sites of the Hungarian University of Agriculture and Life Sciences, Plant Production and Agrotechnical Research Station, Szeged-Öthalom and Fülöpszállás in 2020/2021. The experiments were performed on 10 m2 plots, in four replicates, with four cereals and one winter pea species, in different phenological phases. We were used fluorescein diacetate to determine the total microbial activity of the soil. As the phenophases progress, the enzymatic activity of the soil decreases, and activity is affected by soil type. The soil enzyme activity was lower on meadow chernozem soil and higher on calcareous meadow soil. Cereal-legume intercrop systems are better able to adapt to drought. The values are higher in cereal-legume intercropping system than in cereals sowed alone. Based on our results, it can be concluded that the enzymatic activity of the soil can be increased by using soil inoculation with bacteria and mycorrhiza fungi preparations.

Elevation gradient shapes microbial carbon and phosphorous limitations in the Helan Mountains, Northwest China

Soil extracellular ecoenzymatic activities (EEA) are major players in the biogeochemical cycles and are closely related to the metabolic demand and nutrient supply in microbes. However, their effects on biogeochemistry along the elevation gradient on mountain ecosystems in arid regions remain unclear. To address this, we investigated the variations of soil microbial resource limitation and the relative contributing factors along the elevation gradient of the Helan Mountains, northwest China. The results showed that the relative abundance of total microbial, bacterial, fungal, actinomycetes, and N-acquiring enzymatic activities (N-Acetyl-β-D-glucosaminidase and Leucine- α-aminopeptidase, that are NAG and LAP, respectively) in the soil first increased and then decreased with an increase in elevation. This variation pattern could be due to the changes in soil temperature and moisture along the elevation gradient. Soil enzyme stoichiometry and resource allocation further revealed that the microbial metabolism activity in the Helan Mountains was limited by carbon (C) and phosphorus (P). Furthermore, the two limited elements were significantly higher at the mid and high altitudes (2,139–2,438 m) than at low altitudes (1,380–1,650 m). Additionally, redundancy analysis revealed that the soil water content and bulk density played a crucial role in microbial community structures, while the soil pH had the most influence on soil EEA and ecoenzymatic stoichiometry. Our findings revealed the patterns of soil microbial community structure, extracellular enzyme activities, and microbial metabolism at various elevations, which will help in understanding the microbial resource limitation and nutrient cycling in mountain ecosystems in arid regions.

Optimalisasi Pengawetan Kurma Tomat Menjadi Serbuk Ekstrak Minuman Guna Meningkatkan Daya Simpan Pangan Nabati

Abstract. This research was conducted with a quantitative approach and aims to determine which tomato dates will be used as a basic ingredient in the manufacture of extract drinks. The use of this tomato analyzes the tolerance level of tomatoes to exposure to sugar derivatives (glucose and lactose) on shelf life as processed vegetable foods. Analyzing the antioxidant levels of tomato date extract based on storage time. Analyzing the effect of storage time on the organoleptic quality of tomato date extract. Analyzing the tolerance level of tomato date extract to exposure to sugar derivatives (glucose and lactose) and their impact on organoleptic quality. The results showed that the comparison of tomato date extract powder with various treatments had an effect on the parameters tested, including increasing antioxidants and reducing microbial levels and was also favored by research respondents when organoleptic testing was carried out. It can be concluded that the storage time of tomato date extract powder will increase antioxidant levels and will make the total microbial activity relatively decreased.Keywords: Dates Preservation, Beverage Extract, Shelf Life, Vegetable Food.

Soil microbial activity as influenced by crusted runoff strip length and mulch cover under in-field rainwater harvesting (IRWH)

A field experiment was designed to provide insight into the system of in-field rainwater harvesting (IRWH) in determining the effect of microbial activities. The treatments that were evaluated include narrow bare (NB) narrow mulch (NM), wide bare (WB) and wide mulch (WM) runoff strips. Soil samples were collected at depths of 5 and 15 cm from the center section of the runoff area and directly from the rhizosphere of the maize roots around basins. From fresh soil samples, Colony Forming Unit (cfu) readings were taken by using a colony counter and total microbial activity was estimated using the fluorescein diacetate (FDA) hydrolysis method. Community-level diversity physiological profiles of the soil samples were assessed by using Biolog EcoPlates™. Results revealed that the mean values of microbial activity indicated the greatest was found under NM rhizosphere (1.611 ± 0.038) and lowest under WB (0.079 ± 0.005) at 5cm depth. Microbial activity under NM at 5 cm was higher (63% increase) than at the rhizosphere (8% increase). However, there was a decrease in the microbial activity of 17% at 15 cm for WM compared to WB. FDA values were positively correlated with measured soil water content across both 5 and 15 cm depths (r = 0.61 and 0.67) and highly significant (r = 90 at P-value ≤ 0.01) for rhizosphere. Some interesting positive correlations between yield and microbial activity were also found however further investigation on microclimatic aspects in association with microbial diversity and activity on soil surface treatments are important for non-uniform canopy structures of IRWH.

EFFECTS OF FUNNELIFORMIS MOSSEAE INOCULATION ON CHILI PEPPER GROWTH UNDER REPEATED DROUGHT STRESS

Chili pepper (Capsicum frutescens L.) is a common commodity used as spice and pharmaceutical uses around the world. However, chili pepper cultivation failure often occurs due to drought exposure. The inoculation of arbuscular mycorrhizal fungi (AMF), such as Funneliformis mosseae, has the potential to induce defense against drought stress through symbiotic association with plant roots. The aim of this research was to investigate the effects of F. mosseae inoculation on the growth of chili pepper under repeated drought stress. Chili pepper plants were exposed to three drought regimes for two cycles, with one rewatering event between the cycles. The plant agronomic variables, physiological performance, and microorganism parameters were observed. The results showed that the plant height, fresh and dry shoot weight, along with fresh and dry root weight increased significantly with F. mosseae inoculation under repeated drought stress. The F. mosseae treatment also increased water relative content and decreased proline and lipid peroxidation significantly. Although drought exposure decreased the AMF root colonization rate, the total microbial activity and glomalin-related soil protein were still increased by the F. mosseae inoculation. However, F. mosseae inoculation was negatively correlated to the abundance of phosphate solubilizing microorganisms. The results suggested that F. mosseae gave positive effects on C. frutescens L. growth under repeated drought stress through induced morphological and physiological responses.

Biomonitoring and assessment of toxic element contamination in floodplain sediments and soils using fluorescein diacetate (FDA) enzymatic activity measurements: evaluation of possibilities and limitations through the case study of the Drava River floodplain

The EU Water Framework Directive requires the monitoring and evaluation of surface water sediment quality based on the assessment of risk posed by contamination on the biotic receptors. Floodplain sediments are important receptors of potentially toxic element (PTE) contamination from the upstream catchment areas, and floodplains host climate-sensitive riverine ecosystems and fertile agricultural areas at the same time. This study investigates the effect of PTE contamination on microbial communities in floodplain sediments and soils using the fast, inexpensive and reliable fluorescein diacetate (FDA) method in order to estimate its applicability for sediment quality monitoring and preliminary toxicity-based risk assessment. Sediment and soil samples were collected from the actively flooded alluvial plain and the river terrace areas along a 130-km stretch of the large Drava River floodplain known to be widely contaminated by historical mining, smelting and the associated industry in the upstream Alpine region. Results of detailed data analysis show that the total microbial activity represented by the measured FDA values is related to PTE (As, Cu, Zn, Cd, Pb) concentrations, but this relationship shows significant heterogeneity and depends on the spatial location and on the soil properties such as organic matter content, dissolved salt and nutrient content, and it is specific to the toxic elements. Results show that some microbe species appear to be able to adapt to the elevated PTE concentrations in toxic soil micro-environments, over time. Despite the observed heterogeneity of microbial activity, the results revealed a breakpoint in the FDA dataset around the FDA = 3 FC (fluorescein concentration) value suggesting that microbial activity is controlled by thresholds.