Assessment of Soil Health Indicators Under the Influence of Nanocompounds and Bacillus spp. in Field Condition

Agricultural yield of major crops is low due to the injudicious use of chemical fertilizers that affects soil fertility and biodiversity severely and thereby affecting plant growth. Soil health is regulated by various factors such as physicochemical properties of the soil, availability of micro/macronutrients, soil health indicator enzymes and microbial diversity which are essential for agriculture productivity. Thus, it is required to draw attention towards an eco-friendly approach that protects the beneficial microbial population of soil. Application of different bioinoculants and agriusable nanocompounds has been reported to enhance soil quality with increased nutrient status and beneficial bacterial population, but additive effects of combined treatments on soil microbial population are largely unknown. The present study investigated the impact of nanozeolite and nanochitosan along with two Bacillus spp. on rhizospheric microbial flora and indicator enzymes to signify soil health under field conditions on maize. Soil health was ascertained by evaluating physicochemical analysis; total bacterial counts including N, P, and K solubilizing bacteria; and soil health indicator enzymes like fluorescein diacetate hydrolysis, alkaline phosphatase, β-glucosidase, dehydrogenase, amylase, and arylesterase. Change in copy number of 16S rRNA as a marker gene was used to quantify the bacterial population using quantitative PCR (qPCR) in different treatments. Our study revealed that nanocompounds with Bacillus spp. significantly (p < 0.05) enhanced total microbial count (16.89%), NPK solubilizing bacteria (46%, 41.37%, and 57.14%), and the level of soil health indicator enzymes up to twofold over control after 20, 40, and 60 days of the experiment. qPCR analysis showed a higher copy number of the 16S rRNA gene in treated samples, which also indicates a positive impact on soil bacterial population. This study presents a valuable approach to improve soil quality in combined treatments of nanocompounds and bioinoculants which can be used as a good alternative to chemical fertilizers for sustainable agriculture.

Bacterial Communities and Prediction of Microbial Metabolic Pathway in Rice Wine Koji From Different Regions in China

Rice wine koji, a traditional homemade starter culture in China, is nutritious and delicious. The final quality of rice wine koji is closely related to the structure of its microbial community. However, the diversity of natural microorganisms in rice wine koji from different regions has not been evaluated. In this study, the microbial population of 92 naturally fermented rice koji samples collected from Hubei, Guangxi, and Sichuan was systematically analyzed by high-throughput sequencing. From all the rice wine koji samples, 22 phyla and 479 bacterial genera were identified. Weissella, Pediococcus, Lactobacillus, Enterobacter, Lactococcus, Pantoea, Bacillus, Staphylococcus, and Leuconostoc were the dominant genera in rice wine koji. The bacterial community structure of rice wine koji samples from different regions was significantly different (p < 0.05). The bacterial community composition of the samples from Hubei and Guangxi was similar, but significantly different from that of SC samples (p < 0.05). These differences may be caused by variations in geography, environment, or manufacturing. In addition, the results of microbial phenotype prediction by BugBase and bacterial functional potential prediction by PICRUSt showed that eight of the nine predicted phenotypic functions of rice wine koji samples from different regions were significantly different (p < 0.05) and that vigorous bacterial metabolism occurred in rice wine koji samples.

Minimalistic soil microbial fuel cells for bioremediation of recalcitrant pollutants

Increased human, agricultural and industrial activities along with improper waste disposal leads to high levels of soil contamination and accumulation of recalcitrant contaminants in the environment. This global issue demands the use of green and sustainable technologies and soil microbial fuel cells (SMFC) can be a potential solution. We adopted minimalistic designs, based on low-cost carbon materials without any expensive catalyst and membrane, which makes the SMFCs suitable for in-field applications. We investigated the ability of the indigenous microbial population of the soil to use organic contaminants as the source of carbon and the enrichment of the electroactive consortium was monitored over time onto the electrode surface of the SMFCs. We tested performance in soil contaminated with pesticide and soil contaminated with hydrocarbons and compare the microbial enrichment process with respect to the case of non-contaminated soil.

Characterization of Morganella sp. for its Paraquat Degradation Potential

One of the beneficial roles of the microbial population is their ability to convert toxic herbicides to lesser toxic compounds such as water and carbon (IV) oxide. Paraquat which is an acutely toxic herbicide is used on farmlands and has been found to affect human health. This study was aimed at characterizing bacteria with the potential to degrade paraquat. Previously isolated bacteria from culture collection labelled A-F were screened for their potential to degrade and utilized paraquat as the sole carbon source in Bushnell Hass agar media. Of the six isolates, isolate E (Morganella sp.) was observed to have the highest growth and tolerance to paraquat after 72 h of incubation at 37 ºC. Characterization study revealed that Morganella sp. can utilize and grow with optimum conditions of pH 6.5, the temperature of 30 ºC and can tolerate up to 400 mg/L paraquat concentration with an increase in growth as inoculum size increases. Thus, these findings showed that Morganella sp. can degrade toxic paraquat to a less toxic form and therefore can be a good isolate for the future bioremediation process of the pollutant.

Mitragyna speciosa Korth Leaves Supplementation on Feed Utilization, Rumen Fermentation Efficiency, Microbial Population, and Methane Production In Vitro

The objective of the research was to evaluate the different levels of Mitragyna speciosa Korth leaves powder (MSLP) added to rations with 60:40 or 40:60 roughage to a concentrate (R:C ratio) on in vitro nutrient digestibility, rumen fermentation characteristics, microbial population, and methane (CH4) production. The treatments were arranged according to a 2 × 8 factorial arrangement in a completely randomized design. The two factors contain the R:C ratio (60:40 and 40:60) and the levels of MSLP addition (0, 1, 2, 3, 4, 5, 6, and 7% of the total substrate). There was no interaction between the R:C ratio and MSLP supplementation on gas production kinetics, ammonia nitrogen (NH3-N), and microbial populations. The gas production rate constant for the insoluble fraction (c) was increased by the R:C ratio at (40:60), whilst there was no difference obtained among treatments for cumulative gas production, whilst the gas production rate constant for the insoluble fraction (c) was increased by the R:C ratio at 40:60. The concentration of NH3-N was influenced by the R:C ratio and MSLP addition both at 4 and 8 h after incubation. In vitro dry matter degradability (IVDMD) and organic matter degradability (IVOMD) were significantly improved by the R:C ratio and supplementation of MSLP at 12 h. Increasing the R:C ratio and MSLP concentrations increased total volatile fatty acid (VFA) and propionic acid (C3) concentrations while decreasing acetic acid (C2) and butyric acid (C4) concentrations; thus, the C2:C3 ratio was reduced. MSLP addition reduced protozoa and methanogen populations (p < 0.05). The calculated CH4 production was decreased (p < 0.05) by the R:C ratios at 40:60 and supplementation of MSLP. Finally, the addition of MSLP as a phytonutrient may improve nutrient degradability and rumen fermentation properties while decreasing protozoa, methanogen population, and CH4 production.

Evaluation of biochemical treatments applied in polluted soils irrigated with low quality water for long periods of time through the CO2 efflux

<p class="042abstractstekst"><span lang="EN-US">To sightsee the bearings of the certain remediation amendments, usually applied in the bioremediation of soils irrigated with low quality water for extended periods on the indigenous microbial population, a greenhouse experiment was conducted at National Research Centre (NRC) where the soil ecosystem was supplied with varied mineral remediation amendments and the carbon dioxide (CO₂) refluxes were followed up. In this study, microbial activity through CO₂ efflux was taken as an indicator to evaluate the effectiveness of eight soil amendments in minimizing the hazards of inorganic pollutants in soil ecosystem irrigated with low quality water s for more than 40 years. Results showed that Ni and Zn were the most dominant contaminants that adversely influenced indigenous microbial activities in untreated soil, while Cu was the most persuasive. All trailed remediation amendments significantly minimized the hazards of inorganic pollutants in treated soil ecosystems. In addition, modified bentonite (Probentonite) was the best persuasive one. Mechanisms take place between trailed remediation amendments and inorganic pollutants in the studied soil ecosystems were discussed. In conclusion application of certain raw or modified clay minerals especially Probentonite could be a good tool in decreasing the rate of the studied inorganic pollutants in a contaminated soil ecosystem irrigated with low quality water for extended periods. </span></p>

Estimating Microbial Population Data from Optical Density

The spectrophotometer has been used for decades to measure the density of bacterial populations using the turbidity expressed as optical density – OD. However, the OD alone is an unreliable metric and is only proportionately accurate to cell titers to about an OD of 0.6. The relationship between OD and cell titer depends on the configuration of the spectrophotometer, the length of the light path through the culture, the size of the bacterial cells, and the cell culture density. We demonstrate the importance of plate reader calibration to identify the exact relationship between OD and cells/ml. We use four bacterial genera and two sizes of micro-titer plates (96-well and 384-well) and show that the cell/ml per unit OD depends heavily on the bacterial cell size and plate size. We applied our calibration curve to real growth curve data and conclude the cells/ml – rather than OD – is a metric that can be used to directly compare results across experiments, labs, instruments, and species.

Response of Broiler Chickens to Oral Administration of Ocimum Gratissimum Leaf Extracts

The study was carried out on one hundred and ninety-five day-old broiler chicks of cobb500 to study the effect of Ocimum gratissimum leaf extracts on growth performance, blood profile, microbial population in the faecal and gut samples. The chicks were randomly selected into five groups with thirty-nine chicks per group and each group replicated thrice. The groups were: control (synthetic antibiotics), extracts from 200 g fresh leaf, 400 g fresh leaf, 40 g air-dried leaf and 80 g aid-dried leaf per litre of water respectively. Data collected were subjected to one-way Analysis of Variance. The growth performance except mortality was similar (P>0.05) across the groups. Albumin, urea, cholesterol, alkaline phosphate and sodium were influenced (P<0.05) at the starter phase while only alkaline phosphate was significantly (P<0.05) highest in birds on 400 g of fresh leaf extract at the finisher phase. Neutrophil was highest (P<0.05) in birds on 400 g of fresh leaf extract while those on 200 g had higher values of lymphocytes and eosinophil at starter phase. At finisher phase, birds on antibiotics and 80 g of air-dried leaf extract had higher (P<0.05) white blood cell. Faecal total microbial population was least (<0.05) in birds on antibiotics and 200 g fresh Ocimum gratissimum leaf extract at starter phase. The study concluded that the adoption of Ocimum gratissimum leaf extract as prophylactic treatment against bacteria should be encouraged among poultry farmers.