Moroccan rock phosphate solubilization during a thermo-anaerobic grassland waste biodegradation process

In order to investigate the presence of thermo-tolerant rock phosphate (RP) solubilizing anaerobic microbes during the fermentation process, we used grassland as sole organic substrate to evaluate the RP solubilization process under anaerobic thermophilic conditions. The result shows a significant decrease of pH from 6.5 to 4.8, and solubilizing from 7 to 15.8% of the phosphorus from the RP in the reactors after 90 days of incubation at 45°C. In these conditions, the organic acids produced were qualitatively and quantitatively identified as: acetic, butyric and propionic acids. This biological RP solubilization is due to the presence of a single thermo-tolerant bacterium isolated and identified as Bacillus subtilis from the anaerobic reactors. This B. subtilis strain was shown to be able to solubilize RP in liquid cultures containing insoluble RP as sole phosphate source. The mechanisms involved in these weathering processes confirmed the production of organic acids which were identified and quantified. This study is expected to lead to the development of novel, non-polluting farming practices by entering in the formulation of novel multi-functional biofertilizer by inoculating this thermo-tolerant phosphate-solubilizing bacterium into agricultural wastes as a practical and environmental strategy.Key words: Grassland, phosphate, solubilization, Bacillus subtilis, thermo-anaerobic conditions

Practicing Impact and Impacting Practice? Creating Impact through Practice-Based Scholarship

This curated debate provides a discussion on impact and its relation to practice-based scholarship, i.e., scholarship grounded in the social theories of practice. Five experienced senior scholars reflect on conceptualizations of impact, how it can be created and disseminated, and on the role of practice-based scholarship in this process. The authors discuss the role of researchers as members of the academic system, their activities related to generating, developing, and challenging new theory, and their reflexive relation to the research context when explaining their research to stakeholders to create knowledge and thus, for impacting practice. To suggest ways of practicing impact, their contributions also conceptualize impactful theory and reflect on the relationship between the production and usage of knowledge. These insights are an important contribution to the debate on scholarly impact and provide critical guidance for impactful scholarly work beyond conventional concepts

Mesophilic mineral-weathering bacteria inhabit the critical-zone of a perennially cold basaltic environment

The weathering of silicate in the world’s critical-zone (rock-soil interface) is a natural mechanism providing a feedback on atmospheric CO2 concentrations through the carbonate-silicate cycle. We examined culturable bacterial communities from a critical-zone in western Iceland to determine the optimum growth temperature, ability to solubilise phosphate-containing minerals, which are abundant within the critical-zone area examined here. The majority of isolated bacteria were able to solubilize mineral-state phosphate. Almost all bacterial isolates were mesophilic (growth optima of 20-45°C), despite critical-zone temperatures that were continuously below 15°C, although all isolates could grow at temperatures associated with the critical-zone (-2.8 – 13.1°C). Only three isolates were shown to have thermal optima for growth that were within temperatures experienced at the critical-zone. These findings show that the bacteria that inhabit the western Icelandic critical-zone have temperature growth optima suboptimally adapted to their environment, implying that other adaptations may be more important for their long-term persistence in this environment. Moreover, our study showed that the cold basaltic critical-zone is a region of active phosphate mineral-weathering

Bacterial dissolution of fluorapatite as a possible source of elevated dissolved phosphate in the environment

In order to understand the contribution of geogenic phosphorus to lake eutrophication, we have investigated the rate and extent of fluorapatite dissolution in the presence of two common soil bacteria (Pantoea agglomerans and Bacillus megaterium) at T = 25 °C for 26 days. The release of calcium (Ca), phosphorus (P), and rare earth elements (REE) under biotic and abiotic conditions was compared to investigate the effect of microorganism on apatite dissolution. The release of Ca and P was enhanced under the influence of bacteria. Apatite dissolution rates obtained from solution Ca concentration in the biotic reactors increased above error compared with abiotic controls. Chemical analysis of biomass showed that bacteria scavenged Ca, P, and REE during their growth, which lowered their fluid concentrations, leading to apparent lower release rates. The temporal evolution of pH in the reactors reflected the balance of apatite weathering, solution reactions, bacterial metabolism, and potentially secondary precipitation, which was implied in the variety of REE patterns in the biotic and abiotic reactors. Light rare earth elements (LREE) were preferentially adsorbed to cell surfaces, whereas heavy rare earth elements (HREE) were retained in the fluid phase. Decoupling of LREE and HREE could possibly be due to preferential release of HREE from apatite or selective secondary precipitation of LREE enriched phosphates, especially in the presence of bacteria. When corrected for intracellular concentrations, both biotic reactors showed high P and REE release compared with the abiotic control. We speculate that lack of this correction explains the conflicting findings about the role of bacteria in mineral weathering rates. The observation that bacteria enhance the release rate of P and REE from apatite could account for some of the phosphorus burden and metal pollution in aquatic environments

Biocontrol of Rhizoctonia solani damping-off and promotion of tomato plant growth by endophytic actinomycetes isolated from native plants of Algerian Sahara

Thirty-four endophytic actinomycetes were isolated from the roots of native plants of the Algerian Sahara. Morphological and chemical studies showed that twenty-nine isolates belonged to the Streptomycesgenus and five were non-Streptomyces. All isolates were screened for their in vitro antifungal activityagainst Rhizoctonia solani. The six that had the greatest pathogen inhibitory capacities were subsequentlytested for their in vivo biocontrol potential on R. solani damping-off in sterilized and non-sterilized soils,and for their plant-growth promoting activities on tomato seedlings. In both soils, coating tomato seedswith antagonistic isolates significantly reduced (P < 0.05) the severity of damping-off of tomato seedlings.Among the isolates tested, the strains CA-2 and AA-2 exhibited the same disease incidence reduction asthioperoxydicarbonic diamide, tetramethylthiram (TMTD) and no significant differences (P < 0.05) wereobserved. Furthermore, they resulted in a significant increase in the seedling fresh weight, the seedling length and the root length of the seed-treated seedlings compared to the control. The taxonomic positionbased on 16S rDNA sequence analysis and phylogenetic studies indicated that the strains CA-2 AA-2were related to Streptomyces mutabilis NBRC 12800ᵀ(100% of similarity) and Streptomyces cyaneofuscatus JCM 4364ᵀ(100% of similarity), respectively

Plant growth-promoting actinobacteria: a new strategy for enhancing sustainable production and protection of grain legumes

Grain legumes are a cost-effective alternative for the animal protein in improving the diets of the poor in South-East Asia and Africa. Legumes, through symbiotic nitrogen fixation, meet a major part of their own N demand and partially benefit the following crops of the system by enriching soil. In realization of this sustainability advantage and to promote pulse production, United Nations had declared 2016 as the “International Year of pulses”. Grain legumes are frequently subjected to both abiotic and biotic stresses resulting in severe yield losses. Global yields of legumes have been stagnant for the past five decades in spite of adopting various conventional and molecular breeding approaches. Furthermore, the increasing costs and negative effects of pesticides and fertilizers for crop production necessitate the use of biological options of crop production and protection. The use of plant growth-promoting (PGP) bacteria for improving soil and plant health has become one of the attractive strategies for developing sustainable agricultural systems due to their eco-friendliness, low production cost and minimizing consumption of non-renewable resources. This review emphasizes on how the PGP actinobacteria and their metabolites can be used effectively in enhancing the yield and controlling the pests and pathogens of grain legumes

THE INFLUENCE OF INNOVATION STRATEGY AND GLOBAL DIVERSIFICATION TOWARDS FIRM VALUE (Empirical Study on Manufacturing Companies Listed in Indonesia Stock Exchange)

Penelitian ini membahas tentang pengaruh strategi inovasi dan diversifikasi global terhadap nilai perusahaan. Strategy inovasi diukur melalui intensitas R&D sedangkan pengukuran diversifikasi global menggunakan variabel dummy. Variable kontrol terdiri dari leverage dan size. Penelitian ini berfokus pada perusahaan manufaktur yang terdaftar di Bursa Efek Indonesia pada tahun 2011-2015. Penelitian ini menggunakan pendekatan kuantitatif dengan data sekunder yang diperoleh dari laporan keuangan yang sudah diaudit pada www.idx.co.id dan www.quotes.wsj.com. Terdapat 138 observasi dari 33 sampel perusahaan. Model analisis yang digunakan adalah model analisis regresi linear berganda. Perhitungan dan uji hipotesis menggunakan SPSS ( Statistical Program for Social Science). Hasil penelitian menunjukan bahwa strategi inovasi secara positif dan signifikan memengaruhi nilai perusahaan. Namun, diversifikasi global tidak berpengaruh signifikan terhadap nilai perusahaan