Total Microbial Population Research Articles

Biocontrol Potential of Neem Leaf-Based Vermicompost as Indicated by Chitinase, Protease and Β-1,3-Glucanase Activity

The rising concern regarding the negative impact of synthetic pesticides has led to the search for alternative means of pest control. Vermicomposting the mixture of oil palm empty fruit bunch and neem (Azadirachta indica) leaves, with the latter known to have pesticidal value, is therefore of great interest and significance to be studied. The present study was conducted to evaluate the chitinase, protease and β-1,3-glucanase activity of neem leaf-based vermicompost as an indication of its biocontrol properties. The total microbial population of different composition of the vermicompost was also investigated. The results showed that at 10% neem composition, an increment in microbial population, chitinase and protease activities was observed in the end product. A higher concentration of neem exerted a suppressive effect on the microbial population as well as enzymatic activity. This study suggested that the addition of an appropriate composition of neem leaves as one of the raw materials for vermicomposting would potentially enhance the performance of vermicompost as biofertilizer as well as biopesticide.

Synergistic pretreatment of CaO and freezing/thawing to enhance volatile fatty acids recycling and dewaterability of waste activated sludge via anaerobic fermentation

To avoid the generally deteriorated dewaterability of sludge in waste activated sludge (WAS) anaerobic acidogenesis, the combination of varied calcium oxide (CaO) dosage (i.e., 0.01–0.07 g/g TS) and freezing/thawing pretreatment (5 F/T cycles) was investigated for concurrently improving the production of volatile fatty acids (VFAs) and dewatering performance of sludge. The highest release of soluble chemical oxygen demand (SCOD) (1836 ± 96 mg/L) and accumulation of VFAs (448.0 mg COD/g VS) were reached through the co-pretreatment of CaO (0.07 g/g TS) and F/T (50 h at −24 °C) (i.e., 0.07 CaO–F/T). Meanwhile, optimal dewaterability of sludge was also achieved in 0.07 CaO–F/T co-pretreated WAS fermentation, which was reflected by large particle size (98.32 μm), low capillary suction time (41.6 s), decreased specific resistance to filtration (SRF, reduced 47.5% against blank) and high zeta potential (−9.59 mV). Co-pretreatment of CaO and F/T reduced the species number of total microbial population, but improved the abundance of acid-producing bacteria. Increased abundance of Bacteroides, Macellibacteroides, Petrimonas, Prevotella, Clostridium, and Megasphaera was positively relevant to the high yields of VFAs. The economic analysis indicated that CaO–F/T was economically acceptable with considerable estimated net profits, which provided a feasible and efficient alternative for further WAS treatment at large scale.

Effect of gamma radiation on microbial load, physico-chemical and sensory characteristics of common spices for storage.

The effect of gamma radiation on the decontamination of microbial population, physico-chemical, radiation sensitivity and sensory characteristics of common spices for storage were evaluated. Spices were irradiated with gamma doses of 0 (as control), 2, 4, 6, 8 and 10kGy, packed in the glass vials and stored at room temperature (22 ± 2°C) in the laboratory. In this research, Bacillus, Salmonella and Listeria species were identified in un-irradiated spice samples. Results also indicated that gamma radiation reduced the total microbial population compared to control and optimum gamma radiation doses (6kGy for red chili and turmeric; 4kGy for cumin, coriander, garlic and black pepper; 2kGy for ginger powder samples) were identified for decontamination of the organisms in the studied spices. It was concluded that no significant differences before and after gamma radiation were observed in physico-chemical, nutritional and sensory properties but significantly changed in microbial load in spices samples.

Evaluation of temperature on the biological activities and fertility potential during vermicomposting of pig manure employing Eisenia fetida

In this laboratory-scale study, the biological activities and vermicomposting potential of Eisenia fetida in pig manure were investigated to evaluate the influence of temperature (10°C–50 °C) on vermicomposting effect. The enzyme activities of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and the content of malondialdehyde (MDA) in earthworm, macro-nutrients (N, P, K), total organic carbon (TOC), humification index (HIX) and C/N ratio in pig manure have been investigated simultaneously. Results revealed that CAT activity elevated initially and then declined with the increased temperature. The increased POD, SOD activity and MDA content indicated the antioxidant stress response of earthworm and the optimum temperature was found at 30 °C. After vermicomposting the pig manure for 60 d under temperature range of 10°C–50 °C, the vermicompost exhibited a significant increase in macro-nutrients, whereas a reduction was observed in TOC, C/N ratio and HIX, reflecting the efficient decomposition of organic waste driven by earthworms and microorganisms synergistically. The result of total microbial population showed the increase of actinomycetes and bacterial population. The enhancement percentage was in the order: 30 °C > 40 °C > 50 °C > 20 °C > 10 °C, revealing the impact of temperature. The results indicated the advantage of vermicomposting with Eisenia fetida and the regulation mechanism of temperature on the vermicomposting effect of pig manure. The present study will benefit to the utilization of agricultural wastes and achieving environmental sustainability.

Oil Palm Empty Fruit Bunch Alkaline Biochar Influences Total Soil Microbial Population, Number of Root Nodules and Soybean Growth in Wonosari Inceptisol

Alkaline biochar oil palm empty fruit bunches is the result of converting oil palm empty fruit bunch waste from the palm oil mill. The waste converted into resources that can be function to repaired / transformed edacid soils into agricultural land alkaline biochar oil palm empty fruit bunches is the result of converting oil palm empty fruit bunch waste from the palm oil mill. The waste converted into resources that can be function to repaired / transform acid soils into agricultural land. The purpose study is to examine the ability of Biochar Alkaline Oil Palm Empty Fruit Bunches and their effect on the total soil microbial population, the number of root nodules, and the growth parameters of soybean plants in the Inceptisol Tanjung Morawa Medan acid soil. The Screenhouse of the Faculty of Agriculture, University of HKBP Nommensen Medan conducted the greenhouse test phase research by using a completely randomized design research design. Field-testing confirmed by a Dessin factorial randomized trial design. Determination of Total Population of soil microbial cups at both stages of testing is to conduct at the Biology Laboratory of the University of North Sumatra, Meda. (The research method uses all statistical observations in the form of analysis of variance analysis (ANOVA). The results of the different parameter tests followed by Duncan's Multiple Range Test the results showed the influence of Biochar as acid amelioration for acid soil affected the total microbial population and the growth of soybean plants. The research (including chemical and physical properties) with various parameters of other plant elements proved that the alkaline biochar of the palm oil-palm bunches was able to replace agricultural lime (calcite) in repairing acid soils. Further research results show the use of biochar oil palm empty fruit bunches has a more diverse effect; because in addition to improving soil chemical properties such as pH and alkaline nutrient levels, this material also helps improve soil physical conditions in terms of porosity and acidic soil water systems, compared to agricultural lime only has a chemical effect. The advantages of biochar oil palm empty fruit bunches are renewable resources (replacing resources) replacing agricultural lime (calcite) which is a mining material that is classified as an unrenewable resource.

Degradation of sulfadiazine and electricity generation from wastewater using Bacillus subtilis EL06 integrated with an open circuit system

Antibiotics are one of the emerging pollutants that have drawn increased attention in recent years. In this study simultaneous production of electricity and bioremediation of sulfadiazine from the wastewater using microbial fuel cells (MFCs) and open circuit system were analyzed. LC-MS analysis revealed decreased sulfadiazine concentration in open circuit system and closed MFC chamber. In MFCs, 12.6 ± 1.3% removal efficiency of sulfadiazine was reached after 30 h and it improved 89.2 ± 2.1% after 100 h. The initial sulfadiazine concentration influenced on antibiotic removal in MFCs and antibiotic removal was increased up to 350 μg/L. At higher antibiotic concentration, reduced microbial activity results depleted antibiotic degradation. MFCs degraded sulfadiazine (350 μg/L) completely within 80 h of treatment. The maximum COD removal (91.9 ± 2.3%) was obtained in MFCs chamber and it was about 60.8 ± 2.7% in the open circuit chamber. The initial total phosphorus content of the wastewater fed with reactor was 1350 mg/L and it reduced considerably after treatment in MFCs system (89.9 ± 2.8%). Total microbial population was 4.5 × 105 CFU/mL after one day of treatment and it declined after five days due to the depletion of nutrients in the wastewater. In MFC electricity generation reached maximum within 60 h of treatment (1.28 ± 0.1 V). The electrogenic strain Bacillus subtilis EL06 was characterized from the MFC and sulfadiazine tolerance was analyzed. These findings demonstrated that MFCs are useful for the simultaneous bioremediation of wastewater and electricity generation.

Effects of Conservation Agricultural Practices on Soil Microbial Population and Yield of Cotton

Field investigations were conducted to assess the effect of conservation agricultural practices on soil biological properties and yield of cotton during the kharif season of 2018 and 2019. The experiments were laid out in a split plot design with four main factors viz., conventional tillage with irrigation schedule of 0.8 IW/CPE ratio (M1), conventional tillage with irrigation schedule of 0.6 IW/CPE ratio (M2), minimum tillage with irrigation schedule of 0.8 IW/CPE ratio (M3) and minimum tillage with irrigation schedule of 0.6 IW/CPE ratio (M4). Sub plot had six treatments of weed and nutrient management viz., crop residue mulch with 100% RDF (S1), crop residue mulch with 75% RDF (S2), pre-emergence application of pendimethalin fb one hand weeding with 100% RDF (S3), pre-emergence application of pendimethalin fb one hand weeding with 75% RDF (S4), mechanical weeding twice with 100% RDF (S5) and mechanical weeding twice with 75% RDF (S6). Total microbial populations viz., bacteria, fungal, and actinobacteria were higher in cotton rhizosphere soil with the minimum tillage of irrigation at 0.8 IW/CPE ratio (M3) in the main plot treatments. Cotton rhizosphere soil with crop residue mulch with 100% RDF (S1) recorded a higher microbial population and it was statistically similar with pre-emergence application of pendimethalin fb one hand weeding with 100% RDF (S3) in the sub plot treatments. Among the treatment combination, minimum tillage with irrigation at 0.8 IW/CPE ratio (M3) and crop residue mulch with 100% RDF (S1) recorded a higher microbial population. Similarly, a higher seed yield of cotton was also recorded with minimum tillage and irrigating the crop at 0.8 IW/CPE ratio and pre-emergence application of pendimethalin fb one hand weeding along with application of 100% RDF (M3S3)

Influences of Farming Practices on Soil Properties and the 2-Acetyl-1-pyrroline Content of Khao Dawk Mali 105 Rice Grains

Khao Dawk Mali 105 (KDML105) is a premium fragrant rice variety and is widely grown in Thung Kula Rong Hai (TKR), northeast Thailand. In the present study, the influence of organic and conventional rice farming (ORF and CRF, respectively) in TKR farmers’ paddy fields on soil properties and their relationship with 2-acetyl-1-pyrroline (2AP) in KDML105 rice grains were investigated. The results indicated that the ORF system had a strong positive effect on major soil quality indicators and the 2AP content in the rice grains. The soil organic matter (SOM) was approximately twice as much in the ORF than in the CRF system, thus leading to much higher total nitrogen (TN), humic acid (HA), and microbial populations in the ORF system. The higher SOM in the ORF system not only enhanced the soil quality indicators but also contributed to approximately 3.5 times higher 2AP than in the CRF system. Principle component analysis indicated a close correlation among SOM, TN, HA, and microbial population under the ORF system; these variables exhibited strong correlations with the 2AP contents in KDML105 rice grains.

Use and Efficiency of Disinfectants within a Hydrocooler System for Postharvest Disease Control in Sweet Cherry

ABSTRACT Commercial disinfectants were used within a hydrocooler to prevent postharvest diseases of sweet cherries and to extend the storage and shelflife durations. Different concentrations of sodium hypochlorite, peracetic acid, hydrogen peroxide and Citrox® were used in in vitro experiments whereby the toxicity of disinfectants on B. cinerea and P. expansum spore germination and germ tube elongation was investigated. Citrox® was the only disinfectant containing organic acids and flavonoids. The in vitro experiments demonstrated that disinfectants were effective in inhibiting spore germination and germ tube elongation. In in vivo experiments, fruits were inoculated with a suspension containing 1 × 106 cfu/mL B. cinerea and P. expansum spores and hydrocooled with appropriate disinfectant concentrations. Total microbial, fungal, and bacterial populations on fruit surfaces and in the water used for processing were reduced by all disinfectant applications. Fruits were packed in modified atmosphere packages and stored at 1°C for 30 days and for 4 additional days on a shelf at 20°C. During cold storage, fruits were evaluated in terms of phytotoxicity, and it was observed that Citrox®, hydrogen peroxide, and ozonated water applications cause phytotoxicity in the both the stem and fruit. In contrast, no phytotoxic reaction was observed in sodium hypochlorite and peracetic acid applications. Fruit decay did not occur during cold storage but was seen during the shelflife period. Fruit decay was significantly reduced by sodium hypochlorite and peracetic acid applications. Sodium hypochlorite and peracetic acid applications within a hydrocooler were found to be efficient in preventing postharvest diseases of sweet cherries.

Isolation and Selection of Streptomyces Species from Semi-arid Agricultural Soils and Their Potential as Producers of Xylanases and Cellulases

The Mezquital Valley (MV), Mexico, is a semi-arid region whose main economic activity is agriculture, this zone is characterized by the use of wastewater for crop irrigation. This condition has increased the amount nutrients in soils, organic carbon content and native microorganisms. The Streptomyces species are a group of saprophytic bacteria that represent between 20 and 60% of the total microbial population in soils, capable of producing metabolites of commercial importance. In this work, Streptomyces species were isolated from agricultural soils of the MV and was evaluated the production of endoglucanases (CMCase) and xylanases (Xyl) in Solid-State Cultivation (SSC). From soil samples, 73 possible strains of Streptomyces species were isolated for their ability to produce CMCase and Xyl in SSC. The study also included its characterization by morphological characteristics. Of the isolated microorganisms, 38 strains were selected as strong enzyme producers according to the measurement of the halo generated in plate and by growth on barley straw as only carbon source. Two different sizes of barley straw particle were tested, finding that the greatest enzymatic activity was observed in particle size 12. Three strains of Streptomyces species were chosen which presented the best catalytic capacities, a maximum of 100.69 AU Xyl/gram dry matter (gdm), 82 AU Xyl/gdm and 26.02 AU CMCase/gdm for strains 30, 28 and 12, respectively. The strains were identified by ribosomal gen16s sequence and identified as S. flavogriseus, S. virginiae and S. griseoaurantiacus. It is the first report of endogluconase and xylanolytic activity by S. virginiae isolated from a semi-arid soil.

Dinamika Karbon dan Mikroba dalam Tanah pada Perlakuan Biochar Kompos Plus

Carbon and microbes in the soil fluctuated from time to time due to various things. This study aims to determine the dynamics of carbon and microbes in the soil in the treatment of biochar-compost. In addition to the use of biochar-compost, this research also uses nano biochar and enrichment with microbial consortia. The study was conducted at the screen house using a complete randomized design with three replications with following treatments: control / without organic fertilizer (P0), compost (P1), biochar-compost 1: 4 (P2), nano-biochar-compost 1: 4 (P3 ), biochar-compost + microbial consortia (P4), compost + microbial consortia (P5) and biochar-compost + microbial consortia (P6) with a dose of 2.5 tons/ha respectively. Biochar comes from corncobs. Compost biochar plus application was made before planting. Parameters observed were soil carbon (C-organic), soil acidity (pH) at 7 DAA, 37 DAA and after harvest, and the total soil microbial population at 2 DAA and after harvest. Soil carbon was measured using Walkey and Black method measured by spectrophotometer, soil pH using a soil: water ratio = 1: 5 and measured by a pH meter, the total microbial population using Total Plate Counting (TPC) method. The results showed carbon and soil microbial populations decreased over time, except for microbial communities in a single compost treatment.

Long-Term Effects of Polyvinyl Chloride Microplastics on Anaerobic Granular Sludge for Recovering Methane from Wastewater.

Polyvinyl chloride microplastics (PVC-MPs) are emerging contaminants affecting biological wastewater treatment processes. However, most of the previous studies mainly focused on their short-term impacts on floc sludge, with little work being conducted to explore their potential effects on more complex anaerobic granular sludge (AGS), which has been widely used for high-strength organic wastewater treatment. In this paper, the long-term effects of PVC-MPs on AGS were investigated via continuous feeding tests that are representative of real wastewater treatment processes. The results of a continuous 264 days test showed that the prolonged exposure of PVC-MPs at 15-150 MPs·L-1 significantly (p = 7.86 × 10-37, 3.44 × 10-43, and 5.29 × 10-46) inhibited the COD removal efficiency of AGS by 13.2%-35.5%, accompanied by a 11.0%-32.3% decreased production of methane and 40.3%-272.7% increased accumulation of short-chain fatty acids (SCFAs). In addition, the PVC-MPs exposure suppressed the secretion of extracellular polymeric substances (EPS), causing AGS and the inside microorganisms to lose the protection of EPS, thereby resulting in granule breakage and decreased cells viability. Aligning with the deteriorated performance, the long-term exposure of PVC-MPs reduced the total microbial populations and the relative abundances of key methanogens and acidogens. A toxicity mechanism assessment revealed that the negative impacts induced by PVC-MPs are mainly attributed to the toxic leachate and excess oxidative stress.

Effects of Chronic Use of Herbicides on Soil Physicochemical and Microbiological Characteristics

Introduction: Herbicide application is a vital strategy of weed control. The effects of these chemicals on the non-target soil microorganisms are very intense; have adverse impact on physicochemical parameters of the soil, which in turn affect soil fertility and plant growth.
 Research Gap: There are insufficient literatures on extensive monitoring of the effects of prolonged herbicides use. Existing literatures concerning analysis of effect of prolonged herbicides application on soil are not comprehensive with respect to number of soil characteristics analyzed.
 Aim: This study assessed the effects of Atrazine and Glyphosate on physicochemical properties and microbial population of carrot and maize farm soils, exposed to prolonged use at Songhai Delta.
 Place and Duration of Study: The study was conducted in Songhai Delta farms and the Department of Environmental Management and Toxicology, Federal University of Petroleum Resources, Effurun, from April to July, 2019.
 Methodology: These pesticides were applied according to the manufacturers’ instructions at sublethal concentrations. Their effects on soil pH, cation exchange capacity, total organic carbon, nitrates, phosphates, sulphates and microbial populations at two depths (0-15 and 15-30 cm) were assessed using standard methods. Microbial counts were carried out for total heterotrophic bacteria and fungi using the pour plate method.
 Results: There were variations in the different properties of the carrot and maize farm soils. Soil pH was higher in maize farm (5.91±0.10) than in carrot farm (5.88±0.06) at the depth of 15-30 cm. The pH, total organic carbon, nitrate content had no significant difference while phosphate and microbial counts were significantly different at P=.05.
 Conclusion: This assessment has shown that the herbicides had no influence on pH, total organic carbon, nitrate but a negative one on bacterial and fungal populations with prolonged use. A modification in physicochemical and microbiological characteristics of soil could be used to predict the fertility and health status of soils.

Application of spectroscopic and multispectral imaging technologies on the assessment of ready-to-eat pineapple quality: A performance evaluation study of machine learning models generated from two commercial data analytics tools

Recently, rapid, non-invasive analytical methods relying on vibrational spectroscopy and hyper/multispectral imaging, are increasingly gaining popularity in food science. Although such instruments offer a promising alternative to the conventional methods, the analysis of generated data demands complex multidisciplinary approaches based on data analytics tools utilization. Therefore, the objective of this work was to (i) assess the predictive power of different analytical platforms (sensors) coupled with machine learning algorithms in evaluating quality of ready-to-eat (RTE) pineapple (Ananas comosus) and (ii) explore the potentials of The Unscrambler software and the online machine-learning ranking platform, SorfML, in developing the predictive models required by such instruments to assess quality indices. Pineapple samples were stored at 4, 8, 12 °C and dynamic temperatures and were subjected to microbiological (total mesophilic microbial populations, TVC) and sensory analysis (colour, odour, texture) with parallel acquisition of spectral data. Fourier-transform infrared, fluorescence (FLUO) and visible sensors, as well as Videometer instrument were used. For TVC, almost all the combinations of sensors and Partial-least squares regression (PLSR) algorithm from both analytics tools reached values of root mean square error of prediction (RMSE) up to 0.63 log CFU/g, as well as the highest coefficient of determination values (R2). Moreover, Linear Support Vector Machine (SVM Linear) combined with each one of the sensors reached similar performance. For odour, FLUO sensor achieved the highest overall performance, when combined with Partial-least squares discriminant analysis (PLSDA) in both platforms with accuracy close to 85%, but also with values of sensitivity and specificity above 85%. The SVM Linear and MSI combination also achieved similar performance. On the other hand, all models developed for colour and texture showed poor prediction performance. Overall, the use of both analytics tools, resulted in similar trends concerning the feasibility of the different analytical platforms and algorithms on quality evaluation of RTE pineapple.

Microbial community dynamics during anaerobic co-digestion of corn stover and swine manure at different solid content, carbon to nitrogen ratio and effluent volumetric percentages

The methane production and the microbial community dynamics of thermophilic anaerobic co-digestion (AD) of corn stover, swine manure and effluent were conducted at total solid (TS) content of 5%, 10% and 15%, the carbon to nitrogen ratio (C/N) of 20, 30 and 40 and the effluent volumetric percentage (EVP) of 20%, 40% and 60%. For batches with 5% TS, the highest methane yield of 238.5–283.1 mL g−1 volatile solid (VS) and the specific methane productivity of 138.5–152.2 mL g−1 initial VS were obtained at the C/N ratios of 20 and 30. For the mixtures with 10% and 15% TS, the highest methane yield was 341.9 mL g−1 VS and 351.2 mL g−1 VS, respectively, when the C/N ratio of 20% and 60% EVP conditions were maintained. Co-digestion of swine manure with corn stover caused an obvious shift in microbial population, in which the archaeal population changed from 0.3% to 2.8% and the bacterial community changed from 97.2% to 99.7%. The experimental batches with the highest relative abundance of the archaeal population (2.00% of total microbial population for 5% TS, 1.74% for 10% TS and 2.76% for 15% TS) had the highest rate of methanogenesis subsequently enhancing methane production (283.08 mL g−1 VS for 5% TS, 341.91 mL g−1 VS for 10% TS and 351.23 mL g−1 VS for 15% TS). The results of microbiome analysis enabled understanding the key populations in biomethane generation.

Evaluation of Physicochemical Properties and Microbial Populations of Soil of Bagale Forest Reserve, Girei Local Government Area, Adamawa State, Nigeria

This study evaluated the relationship between selected physicochemical properties and microbial populations of the soil of Bagale Forest Reserve, Girei Local Government Area of Adamawa State, Nigeria. Five plots of 20 x 20 m were laid. Soil samples were collected from five different positions at two soil depths of 0-15 cm and 15-30 cm. The soil samples were isolated in the laboratory for microbial populations and determination of physical and chemical properties. The results obtained revealed that fungal population (7.65 x 105 cfu/ml) was the highest at the soil depth of 0-15 cm, representing 39% of the total microbial populations in the sampled soil of the study area. The results further revealed that the population (6.84 x 105 cfu/ml) of the bacteria had a positive effect on soils of the study area in terms of nitrogen fixation by Rhizobacterial spp. Chemical properties of the soil samples revealed that the available phosphorus exhibited the highest percentage (61.7%) at 0-15 cm soil depth. Analyses of soil physical properties recorded the highest percentage (49.0%) of sand at 0-15 cm soil depth. A similar percentage (50.0%) of sand was exhibited at the depth of 15-30 cm. These percentages accounted for the high porosity (29.0%) of the soil observed at the two soil levels in the study area and could be improved through the application of lime fertilizers. Application of appropriate fertilizers like NPK to improve the soil condition of the study area is highly recommended.

Vermiremediation of Urban and Agricultural Biomass Residues for Nutrient Recovery and Vermifertilizer Production

Recovering the nutrients from organic solid residues is an ever demanding approach in terms of eco-friendly management. In this study, the efficiency of the earthworms, Perionyx ceylanensis and Perionyx excavatus in recycling and recovering plant nutrients from urban and agricultural biomass residues was investigated. Vermicomposting of four different types of organic biomass resources in combination with cowdung (1:1) for 50 days was conducted using the earthworms, P. ceylanensis, and P. excavatus. Physico-chemical, microbiological and maturity characteristics of the final product were analyzed. Results showed a decrease in pH, organic matter content (OMC), total organic carbon (TOC), cellulose, lignin, carbon to nitrogen (C/N) and carbon to phosphorus (C/P) ratios, and an increase in total Kjeldahl nitrogen (TKN), phosphorus (TP), potassium (TP), calcium and sodium in vermicomposts over composts (prepared without earthworms). TKN increase in vermicomposts over composts was insignificant between P. ceylanensis and P. excavatus, while it was significant for TP, TK, and total microbial population (P < 0.05). The reduction of TOC, OMC, C/N, and C/P ratios were significantly higher in vermicomposts recovered from P. ceylanensis than P. excavatus. The results clearly indicated that physico-chemical and microbiological changes are dependent on the nature of organic resources and earthworm species used. The seed germination tests with black gram and sorghum showed that the vermicomposts were mature and non-phytotoxic. P. ceylanensis is equally efficient in recovering nutrients from organic biomass residues to that of a widely used, P. excavatus. Therefore, both P. ceylanensis and P. excavatus are efficiently used for recovering nutrients from urban and agricultural biomass residues and for vermifertilizer production.

PSXI-24 Rumen temperature, fermentation and microbial signatures are poorly associated with steer feed-efficiency profiles

Abstract Breeding feed-efficient cattle can reduce the environmental footprint of beef operations but assessing all replacement candidates for feed-intake is not practical due to cost implications. The main objectives of this study were to evaluate if rumen temperature (RumT), measured with wireless rumen Thermobolus® can distinguish steers with different feed-efficiency profiles and whether steers with divergent efficiency profiles have different nutrient fermentation signatures. The study also validated the relationship between rectal temperature (RecT) and RumT measured with automatic thermistors. Residual feed intake (RFI) profiles of 160 steers were measured over two years. All steers were assessed for RFI profiles using high and moderate forage diets, respectively, over two successive periods each year. Each steer was fitted with a rumen Thermobolus® throughout each ~80-d test period while half of the steers wore an automatic temperature-logger rectal device for ~30d. The devices recorded the RumT and RecT every 5 minutes, respectively. Rumen fluid samples were collected from high-RFI (n = 5) and low-RFI (n = 5) steers to assess if differences in rumen fermentation and microbial profiles exist. Circadian-adjusted RumT and RecT for each steer were used for analysis. The within-period correlations between RumT and RecT ranged between 49 and 77%. There was a trend (P = 0.08) that differences exist for rhythm-adjusted temperatures among different RFI profiles with low-RFI steers (39.72±0.01oC) having lower average RumT than those in high (39.75±0.01oC) or medium (39.74±0.01oC) classes. The correlation between the two test-periods for rhythm-adjusted RumT was 65% while the correlation between RFI from both periods was 47%. There was no difference (P &amp;gt; 0.30) between high- and low-RFI animals for the total or individual volatile fatty acid fractions or microbial populations. The narrow temperature variation among RFI classes limits its use as screening tool but the higher across-period correlation encourages the need for further studies into alternative potential applications.

The exploration and utilization of functional microorganisms isolated from the tropical peatlands

The utilization of peatlands may decline the ecological functions of peatlands as carbon sink, water storage and biodiversity source. Therefore, different scientific approaches are required to increase peat productivity and inhibit decline in the ecological functions of peatlands. This article is aimed to provide information on researches that have been carried out in tropical peats in the South Kalimantan Province. The exploration and the potential utilization of microbes was reviewed from several studies conducted in the Desa Landasan Ulin Utara (LaURa), Kota Banjarbaru, South Kalimantan Province. Peat research carried out in the Desa LaURa during the dry season after peat fires in 2015 showed that microbial SRBM (mixture of N fixing, solubilizing P and cellulolytic microorganisms) from the modified recharge bio-pore system was able to improve the growth of roots, stems, and leaves, nutrient uptake, and increase production and biomass of soybean. In another research in 2018, the use of commercial biofertilizers containing Azotobacter sp and Lactobacillus sp applied to the LaURa peats significantly increased the total N and pH of peats but did not accelerate the decomposition of peat materials. In subsequent study on the exploration of nitrogen fixing microorganisms from the LaURa peats (sapric peats) which amounted to 10375-10500 cells g−1, the total N-fixing microbial population was correlated positively to the pH and EC of peats, and correlated negatively to the contents of peat organic C. Combining the results, the total N2 fixing microbial (NFM) population was significantly affected by organic C and peat EC (total NFM population = -154.052 + 33.126 pH + 607.117 EC, R2 = 51.63%). Results obtained from these studies demonstrated that the functional microbes of peatlands are able to maintain ecological functions of the peats.

Gaseous Ozone as a Suitable Solution for Postharvest Chestnut Storage: Evaluation of Quality Parameter Trends

The storage of chestnuts is a highly critical phase due to the considerable postharvest losses of the product with relevant commercial impact. The effect on the chemical quality parameters of chestnuts treated with 300 ppb of gaseous ozone in air or in atmospheric air at T = 2 °C for 150 days during the storage has been investigated. The ozone treatment increased sucrose and total sugar contents; while tocopherols were reduced. No significant differences in weight loss and fatty acid content were recorded between chestnut treated with ozone and untreated fruits (P ≥ 0.05). In addition, chestnut ozone exposure for 150 days reduced the total microbial populations associated with the pericarps of about 1.6 logs for mesophilic bacteria and 1.0 logs for fungi. Overall, our results suggested that gaseous ozone treatment is a valid and economic technology to ensure the shelf life quality of chestnut during the long storage periods.