Effect of Biochar on the Abundance of Soil Bacteria.

A pot experiment was conducted to study the effect of biochar on the abundance of soil bacteria and compare it with the source biomass. Seven different treatments and a control were used in the experimental set-up. Three different types of biomass were selected and three types of biochar were produced from them. Both the materials were applied to the soil at a rate of 5t/ha. All treatments were incubated for 30, 60 and 90 days. Cultural, microscopic and biochemical tests were carried out to identify the bacterial isolates in soils treated with biochar and its source biomass. Bacterial isolates identified in soil and in some of the biomasses before treatments were applied include Bacillus badius, Bacillus krulwichiae, Bacillus siralis, Bacillus sylvestris, Bacillus flexus, Aneurinibacillus aneurinilyticus and Bacillus thuringiensis while after incubation periods, seven new isolates were identified. This was true for the biomass treated soils where additional one to two isolates reappeared. Conversely, in the biochar treated soils, most of the isolates disappeared except Bacillus badius that survived in all soils till 90 days. Because of its tolerant nature, it was further investigated for cellulase enzyme activity. Interestingly, the isolate did not show any such activity. Conclusively, biochar application may exert negative effect on the distribution and proliferation of soil bacteria with possible effect on soil quality and crop production.

Phenotypic and Genotypic Characteristics of Rhizobia Isolated from Meknes-tafilalet Soils and Study of Their Ability to Nodulate Bituminaria bituminosa.

Aims: The objectives were to isolate and characterize phenotypically and genotypically the rhizobial strains from the soils belonging to the Meknes-Tafilalet region in order to select strains that are able to nodulate Bituminaria bituminosa. Study Design: An experimental study. Place and Duration of Study: Department of biology (Soil & Environment Microbiology Unit) Faculty of Sciences, Moulay Ismail University and Technical Support Unit for Scientific Research, CNRST in Rabat; between January and August 2010. Methodology: Samples from 23 different sites belonging to the Meknes-Tafilalet region were collected in order to select rhizobial strains that are able to nodulate Bituminaria bituminosa. The morphological, cultural and phenotypic parameters of isolated strains were studied. The phenotypic characteristics include colony morphology, growth speed, tolerances to temperature, salt and pH. To assess the genotypic diversity among the isolates, molecular characteristics based on 16S rDNA gene sequencing were performed. Results: The majority of the isolated strains showed fast-growing capacity (75%). Most strains tolerate neutral to alkaline pH, however some strains (18%) showed weak growth capacity at pH 4. All isolates were tolerant to high salt stress ([NaCl] = 3%). The genotypic characterization based on16S rDNA gene sequencing of the twelve strains showed a high diversity between the isolates. Conclusion: Taken together, our results highlight the important biodiversity of the isolated rhizobial strains and open opportunities for the development of new bio-fertilizer.

Isolation and Identification of Glucose Oxidase Hyper Producing Strain of Aspergillus niger.

Aims: Glucose oxidase is an enzyme with large scale applications in various industries. It is also used in several diagnostic kits which makes it medically important as well. Our aim was to isolate indigenous glucose oxidase hyper producing strain of Aspergillus niger from different soil samples of Punjab, Pakistan. Study Design: An experimental study. Place and Duration of Study: Institute of Industrial Biotechnology, GC University, Lahore from March 2011 to July 2012. Methodology: Two hundred and seventy nine fungal strains were isolated from soil of different localities of Punjab. Isolates were screened for glucose oxidase production using submerged fermentation. Glucose oxidase hyper producer isolate was identified using morphological and molecular techniques i.e. 18S rDNA. DNA was isolated and amplified using PCR. Gene sequencing was done and homology analysis was studied. Rate of glucose oxidase production was also analysed. Results: Glucose oxidase hyper producing isolate was identified as A. niger A247 strain. This strain gave best reproducible results (145.22 ±0.034 U/g of cell mass) after 72 hrs of fermentation at 30ºC and at a medium pH of 7.2. Conclusion: Our results indicate the natural ability of A. niger to produce Glucose oxidase in large quantity instead of using genetic manipulation techniques.

Bioprospecting of Cellulase Producing Extremophilic Bacterial Isolates from India.

Aim: To isolate and identify the potential extremophilic cellulase producing strain viz., psychrophiles, halophiles, thermophiles and to compare the Cellulase activity from samples collected from different geographical regions of India. Place and Duration of Study: Bharathiar University, Department of Biotechnology, Molecular Microbiology Lab, Coimbatore, Tamilnadu, India, between January to April 2011. Methodology: Cellulase-producing extremophilic bacteria viz., psychrophiles, halophiles, and thermophiles have been isolated from soil samples. According to morphology and pigmentation, 138 distinct bacteria were isolated and screened for cellulase activity by Gram’s iodine–carboxymethylcellulose plate (CMC) assay. On the basis of the cellulase activity, six potent cellulase-producing isolates from each cluster viz., P14, P36, H6, H13, T2 and T3 were selected for 16S rRNA gene based identification. The strains were optimized for maximum cellulase activity at various temperature and pH range. Results: The phylogenetic relationship revealed that P14 and P36 psychrophilic isolates possessed maximum identity with Bacillus simplex (100%) and Arthrobactercitreus (99%), with a cellulase activity of 14.10± 1.73 and 18.27± 0.71 UmL-1 respectively. Likewise, among halophiles, H6 and H13 were identified as Bacillus subtilis and Bacillus endophyticus (99%), with a cellulase activity of 14.87 ± 0.55 and 16.83 ± 0.44 U mL-1, correspondingly. In thermophiles, T2 and T3 showed close proximity with Bacillus amyloliquefaciens and Bacillus megaterium (99%), with a cellulase activity of 21.53 ± 1.30 and 19.93 ± 0.38 U mL-1 respectively. Conclusion: In the present study, the thermophilic isolates showed promising Cellulase activity compared to psychrophiles and halophiles.

α-Amylase Production on Low-Cost Substrates by Naxibacter sp. Isolated from Mauritian Soils.

Alpha amylase is an important enzyme used in different industries, which degrades starch into smaller disaccharides. Extracellular α-amylase producing organisms were isolated from soil samples from Mauritius and identified by standard biochemical tests. In this study, the high yielding strain was used for amylase production. The potential of four readily available substrates, namely sugarcane bagasse, potato peel, kitchen wastes and banana peel to induce amylase production was investigated. Different parameters like temperature (30ºC, 40ºC, 50ºC, 60ºC & 70ºC), different pH (5.0, 6.0, 7.0, 8.0 & 9.0) and inoculum sizes (10%, 20%, 50%, 100% & 150% v/w) were used for the α-amylase production. It was found that α-amylase production and activity was highest for potato peel at 50ºC at pH 6.0 and inoculum size 50% (v/w). Amylase assays performed at different incubation temperatures (30ºC - 60ºC) and pH (5-9) showed that the amylase worked best at 50ºC and pH 7.Based on results of biochemical tests and 16S ribosomal RNA gene sequences, the isolate was identified to belong to the Betaproteobacteria, closely related to Naxibacter haematophilus (99% sequence similarity to the type strain).

Survival and Speed of Escherichia coli Infiltration in a Hydromorphic Soil in Wet Tropical Zone.

Aims: Untreated wastewater is usually used for crop irrigation in developing countries; however it contains a lot of pathogenic bacteria. This study was carried out to determine the fate of E. coli contained in wastewater in a hydromorphic soil. Study Design: Environmental microbiology Place and Duration of the Study: This study was carried out in the experimental field of the Dschang University, during the dry season (November 2011- Mars 2012) and the rainy season (June 2012-September 2012). Methodology: Six plots of 4 m2 each were tilled in 400 m2 surface area in the dry and in the rainy seasons. Wastewater was collected from the experimental wastewater treatment station in the University of Dschang; it was applied on three plots, and three other plots were used as controls. Once every week, soil samples were taken on the surface (0 - 10 cm), in the medium (20 - 30 cm) and at the water table level (40 - 50 cm). Levels of E. coli in soil samples were determined on “Lactose Tergitol® 7 Agar with TTC” medium, and midbiochemical confirmation tests were carried out (tests of indol, Simmons citrate, gas production, mobility, fermentation of mannitol, glucose and lactose). Results: In the rainy season, E. coli was detected on the soil surface until the 112th day, while in the dry season detection did not exceed the 63rd day. E. coli was detected in the deeper layers of the soil (20 - 30 and 40 - 50 cm) from the 14th and the 70th day respectively. This helps to estimate the speed of vertical migration to be between 5 and 18 mm per day. Conclusion: E. coli bacteria contained in urban wastewater survive for a long-time in hydromorphic soils and reach significant depths, and can consequently pose serious problems of public health.

Enhancing Bio-Available Phosphorous in Soil Through Sulfur Oxidation by Thiobacilli.

Aims: The objectives were to evaluate the phosphate solubilization efficiency of different Thiobacilli strains and to find out the best combination of sulfur and Thiobacilli for enhancing bio-available P in soil. Study Design: An experimental study. Place and Duration of Study: Microbiology and Soil Fertility Labs, Department of Soil Science and Soil and Water Conservation, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan and Microbiology and Soil Chemistry Labs, Auriga Research Center, Lahore, Pakistan, between May 2011 and November 2012. Methodology: Fifty Thiobacilli strains were isolated from ten different ecologies. Then an incubation study of soil was performed wherein the most efficient four Thiobacilli strains were inoculated in combination with three different levels of elemental sulfur to determine pH, water soluble sulfur, sequential P fractions and bio-available phosphorous contents in the incubated soil. Results: All the four Thiobacillus strains (IW16, SW2, IW1 and IW14) dropped pH of the incubated soil along with three doses of S° (50, 75 and 100 kg ha-1). However, Thiobacillus strains IW16 and SW2 reduced soil pH quite sharply from 7.90 to 7.12 (net reduction of 0.78 points) and 7.28 (net reduction of 0.62 points) respectively where inoculated with S° @ 100 kg ha-1. The best P solubilizer was Thiobacillus strain IW16 and the best dose of S° was @ 100 kg ha-1 and their combination enhanced maximum quantity of P (22.26 mg kg-1) in the soil by solubilizing already present insoluble calcium bounded P fractions like octacalcium phosphate (Ca8-P) and apatite (Ca10-P). Conclusion: The present study suggests the use of Thiobacilli along with elemental sulfur for the dissolution and enhancement of bio-available P in alkaline and calcareous soils.

Hydrocarbon contamination of a typical mangrove floor in Niger Delta, Nigeria

The impact of petroleum hydrocarbons on the floor of a mangrove system located on one of the intertidal lands behind the barrier islands of Niger Delta basin of southern Nigeria was evaluated following the Obiafu-14 oil spillage. The area covered by the oil spill was delimited by reconnaissance and soils were sampled by grid method from the bottom and middle slopes of oil-affected and unaffected [control] sites. Soil samples were later brought to the laboratory where total hydrocarbon content was determined by extraction and spectrophotometric techniques. A lower pH range of 4.28-4.36 in the oil impacted soils meant that the site was more acidic; a higher moisture content of 33.34% and lower electrical conductivity [EC] of 31.75 micro S/cm in the affected area presupposed oxygen deprivation and lower salt content respectively. On the strength of the baseline data on the study area and evidence from the uncontaminated, geographically similar control site, it can be said that the Obiafu-14 oil spillage had severely contaminated the affected mangrove floor. This is corroborated by a total extractable hydrocarbon content of 6.32x103 +/- 344 mg/kg [no overlap in Standard Error at 95% Confidence Limit], and the abysmal degradation of the mangrove system at the site. Although soils of the mangrove floor under consideration may well be of limited cultivation value on account of the people's dual occupation in fishing and farming, the presence of such levels of petroleum hydrocarbons at the study site might hamper agricultural productivity

Morfogenesis de hongos dematiáceos: II. Estudio comparativo de cepas aisladas de suelos con Fonsecaea pedrosol / Morphogenesis in dematiaceous fungi: II. Comparative study of strains isolated from soils with Fonsecaea pedrosol

Se efectuó un estudio comparativo entre 5 cepas de hongos dematiáceos (levaduriformes y filamentosos) aislados de suelos con un cepa de Fonsecaea pedrosoi. En cuanto a su patogenicidad una de ellas con características del género Wangiella mostró un proceso inflamatorio en las patas de los ratones inoculados en menor grado que Fonsecaea pedrosoi y manteniendo su forma levaduriforme