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Microbial agents present in soil rhizosphere play a key role in reducing intensive use of inorganic fertilizers, which cause environmental pollution and negatively affect soil fertility. To improve plant growth, microbial agents with silicon (Si) can be used in combination with chemical fertilizers. In this glasshouse study, co-inoculants Enterobacter sp. UPMSSB7, mycorrhizae (Glomus mosseae) and addition of Si were evaluated for growth improvement of rubber seedlings. Results of this study indicated that co-inoculation significantly (P < 0.01) improved stem height, chlorophyll content, leaf area, root and shoot dry weight, total root length, root surface area, and root volume as compared to control treatment. The co-inoculation significantly (P < 0.01) increased Si content in shoot and root as well as leaf nutrients content (N, P, and K) as compared to control treatment. Si alone had no effect on seedling growth and nutrients content. The population of Enterobacter sp. UPMSSB7 in rhizosphere of seedlings as a result of co-inoculation, was not significantly different from Enterobacter sp. UPMSSB7 with Si treatment. The mycorrhizae root colonization and spore density were significantly (P < 0.01) increased in co-inoculation, compared to control and single inoculations with Si. Thus, our results suggested that co-inoculants Enterobacter sp. and mycorrhizae could be an eco-friendly approach for growth promotion of rubber seedlings. [ABSTRACT FROM AUTHOR]

Rigidoporus microporus is a causal agent of white root rot disease of rubber trees. Chemical control is commonly used against this disease but it is expensive, causes environmental pollution and fungal resistance. Silicon is a beneficial element which enhances plant growth and disease resistance but mostly present in insoluble forms. Silicate solubilizing bacteria (SSB) can solubilize the insoluble forms of silicates. This study aimed to screen and evaluate potential SSB with solubilizing activity, plant growth promoting traits and antagonistic activity against R. microporus. Bacteria were isolated from healthy rubber plantation area. Five out of 26 bacterial isolates which showed the ability to solubilize silicate on magnesium trisilicate media were screened in vitro for growth promoting traits and production of indole-3-acetic acid (IAA), siderophores and hydrolytic enzymes. The investigation of antagonistic activity against R. microporus was conducted using dual culture test. The potential SSB isolates were identified by 16S rRNA gene sequencing. The isolate UPMSSB7 showed the highest solubilization of silicate, phosphate (P) and potassium (K) (solubilizing index 4.67, 2.52 and 2.61, respectively). It also showed highest silicate solubilization at 5 and 10 days (9.76 and 11.55 mg L−1, respectively) in liquid assay. It strongly inhibited the growth of R. microporus with percent inhibition of radial growth of 57.24% and produced highest IAA (19.96 µg mL−1). All the isolates produced siderophores. Two isolates, UPMSSB7 and UPMSSB10, were able to secrete cellulase enzyme, but pectinase was produced by UPMSSB7 only. The isolate UPMSSB7 was identified as Enterobacter sp. This isolate was found to be the most potent antagonistic isolate against R. microporus and simultaneously the most efficient one in solubilizing insoluble silicates, as well as P and K. [ABSTRACT FROM AUTHOR]

Cogeneration is considered as one of the promising energy efficient techniques for producing electricity and useful thermal energy from a single fuel source. This paper describes a feasibility study of the implementation of different cogeneration options to a paper mill to evaluate their energy saving potentials and economic benefits. The investigated systems in this paper are gas turbine, steam turbine and combined cycle cogeneration options evaluated and compared based on energy utilisation factor and Annualised Life Cycle Cost (ALCC) analysis. The results of energy analysis show that all Combined Heat and Power (CHP) systems satisfy the thermal energy needs of the mill while the combined cycle cogeneration option generates the highest amount of electric energy equal to 10.91 MW. The gas turbine cogeneration system is shown as the most advantageous system from overall energy point of view with the highest energy utilisation factor of 78% meeting the heat and electric requirements of the mill and exporting 21,329 MWh of additional electricity to the grid. Economic feasibility results also show that an overall saving of 5.12 million US$ can be achieved by implementing the gas turbine cogeneration system to the mill making it as the best cogeneration option with the least overall ALCC of 1.34 million US$ and the maximum percentage of CO 2 emission reduction (68%) when compared with the other options. [ABSTRACT FROM AUTHOR]

• Bioformulation of microbes with Si reduced white root rot disease in rubber seedlings. • Bioformulation was not significantly different than fungicide in disease suppression. • Bioformulation increased plant growth and nutrient contents than fungicide and control. • The mycorrhizae spore density and root colonization were increased by bioformulation. White root rot (WRR) disease, caused by Rigidoporus microporus , is one of the major constraints causing the economic loss to rubber plantation worldwide including in Malaysia. This glasshouse study was conducted to evaluate the efficacy of a peat-based bioformulation of Enterobacter sp. UPMSSB7 and an arbuscular mycorrhizal fungus (AMF, Glomus mosseae) with silicon (Si) for WRR suppression and plant growth promotion of rubber seedlings. Results revealed that the tested bioformulation significantly (P < 0.0001) reduced the disease compared to positive control while, was not significantly different than the propiconazole, a triazole fungicide. The lower values of disease incidence, disease severity of foliar and root rot symptoms, area under disease progress curve, pathogen colonization and higher value of disease reduction were recorded in both bioformulation and the triazole fungicide treated seedlings than positive control treatment 24 weeks after inoculation with R. microporus. Results indicated that pathogen-inoculated seedlings treated with bioformulation had significantly (P < 0.0001) increased stem height, girth size, chlorophyll content, leaf area, shoot and root dry weight, total root length, root volume and root surface area (103.8 cm, 8.08 mm, 56.62 SPAD value, 3534.8 cm2, 37.04 g and 36.76 g, 1617.7 cm, 24.15 cm3 and 402.97 cm2, respectively) as compared to fungicide and control treatments. The tested bioformulation also significantly (P < 0.0001) increased silicon content in root and shoot (18.56 g kg−1 and 27.61 g kg−1, respectively) as well as leaf nutrient (N, P, K and Ca) contents (3.89%, 0.19%, 1.06% and 0.57%, respectively) as compared to the triazole fungicide and control treatments. The population of Enterobacter sp. (1.1 × 108 cfu g−1 soil) recorded in pathogen-inoculated seedlings treated with bioformulation was not significantly different than non-inoculated seedlings treated with bioformulation. AMF spore density and root colonization were recorded higher in bioformulation treated seedlings with or without pathogen inoculation than the triazole fungicide and control treatments. From this study, it was concluded that the peat-based bioformulation of Enterobacter sp. and an AMF (Glomus mosseae) with Si could be a potential approach to suppress WRR and improve growth of rubber seedlings. [ABSTRACT FROM AUTHOR]

The most common technology for thermochemical conversion of solid fuel through the process of gasification, such as coal, varieties of residues from biomass and agriculture are the bubbling fluidised bed or fluidised bed systems. However, there are some disadvantages within these systems including the formation of eutectic mixtures, increased process of melting and bed agglomeration. Hence, the current study aimed to evaluate the agglomeration behaviour of various biomass fuels. Characteristics of five biomass fuels (miscanthus, peanut, straw, domestic wood and industrial wood) in a bubbling fluidised bed (BFB) combustor were studied by SEM-EDX, XRD and XRF analysis of bed materials and ash samples. The influence of bed temperatures on the fuel ash composition and bed particles was evaluated, as well as fuel ash components, their interaction with the particles from the bed sand and morphology of the bed material. The combustion efficiency ranged from 95.5 to 99.5% with the highest value obtained for miscanthus under SA conditions. The peanut and straw had the highest K content, whereas the industrial wood ash contained the highest Ca content compared to other biomasses. The XRF results showed that most of the potassium (K) from the wheat straw biomass was converted to K 2 O with 19%. No bed agglomeration was noticed without staging-air (WSA) and with staging-air (SA) combustion conditions, even with temperatures up to 850 °C during the testing period. Overall obtained results demonstrated that agglomeration is unlikely expected to be a major problem during fluidised bed combustion of tested biomass fuels. [ABSTRACT FROM AUTHOR]