Isolation and Characterization of Bacterial Strains that are Resistant to Copper, Mercury and Other Antibacterial Agents From Different Soil Environments.

Bacteria were isolated from soil samples taken from different locations in the Kuching industrial area. Copper- and mercury-resistant strains were selected and minimal inhibitory concentrations (MICs) for either heavy metal were determined. Mercury is more toxic than copper in both solid and liquid media. The inhibitory concentrations in solid media were higher than in liquid media. With higher MIC values, the bacterial isolated from the metal factory area were shown to be more resistant to metals compared to those from the other areas. This acts as a bioindicator of higher levels of heavy metal pollution in the metal factory area. The most dominant metal-resistant bacteria were Pseudomonas sp. About 50% of bacterial strains had multiple heavy metal resistance phenotypes (there were two to seven types of heavy metal). The isolates were also found to be resistant to several antibiotics, including ampicillin, kanamycin and tetracycline. The highest percentage of individual resistance detected was CuR, followed by CoR, FeR, MgR, ZnR, HgR, AgR and UVR. DNA analysis of five strains failed to show the presence of plasmids. Hence, there was no clear indication that the multiple resistances were coded by gene carried on plasmids

An overview of biomass thermochemical conversion technologies in Malaysia

The rising pressure on both cleaner production and sustainable development have been the main driving force that pushes mankind to seek for alternative greener and sustainable feedstocks for chemical and energy production. The biomass ‘waste-to-wealth’ concept which convert low value biomass into value-added products which contain high economic potential, have attracted the attentions from both academicians and industry players. With a tropical climate, Malaysia has a rich agricultural sector and dense tropical rainforest, giving rise to abundance of biomass which most of them are underutilized. Hence, the biomass ‘waste-to-wealth’ conversion through various thermochemical conversion technologies and the prospective challenges towards commercialization in Malaysia are reviewed in this paper. In this paper, a critical review about the maturity status of the four most promising thermochemical conversion routes in Malaysia (i.e. gasification, pyrolysis, liquefaction and hydroprocessing) is given. The current development of thermochemical conversion technologies for biomass conversion in Malaysia is also reviewed and benchmarked against global progress. Besides, the core technical challenges in commercializing these green technologies are highlighted as well. Lastly, the future outlook for successful commercialization of these technologies in Malaysia is included

Biochar production from sago (Metroxylon Spp.) via pyrolysis

The limited of fossil fuels and the growing awareness of the detrimental environmental consequences resulting from greenhouse gas emissions have reinforced the importance of biomass as an energy resource in developed and developing countries. It is expected that future energy use will have increased utilization of different energy sources, including biomass, municipal solid wastes, industrial wastes, agricultural wastes and other low grade fuels. Recently, the ease of accessibility of sago biomass has drawn considerable interest of researches regarding the production of renewable energy. Pyrolysis is a good practical solution to solve the growing problem of landfills, with simultaneous energy extraction and nonleachable minimum residue. Pyrolysis also provides good solution to the problem of sago residue particularly in the region of Sarawak, Malaysia. Therefore, an effort is made in this study to utilize sago biomass as agricultural residue for the production of cost effective and environmental friendly fuel. Furthermore, the slow pyrolysis of sago biomass from different sources of the plant (bark, frond and cortex) by using Electrical Furnace Reactor was studied with the aim of producing solid pyrolysis product known as biochar, having promising properties and potential for use in traditional fossil coal applications. The study focuses on investigating of the role of best process parameters including reaction temperature, process time and nitrogen flow rate on production of biochar. The experiments were designed using central composite design (CCD) method and the optimization was performed by using response surface methodology. The characteristics of biochar based on its quality, distribution of chemical species, carbon conversion efficiency and thermal efficiency has been examined. Optimal conditions was obtained at the temperature of 400 ºC, 20 minutes of process time and nitrogen flow rate of 75 mL/min to result in the maximum yield of biochar at 47%. Moreover, the calorific value was remarkably improved from 22.16 MJ/kg to 25.92 MJ/kg as the biomass was turned into biochar. The locally sourced starch flours were utilized as binder to produce three different grades of briquettes from the produced biochar at different mixing ratios. The textural, morphological and thermal stability characteristics of the prepared briquettes were investigated by surface area analysis (Brunauer-Emmett-Teller equation), scanning electron microscopy (SEM), and Thermogravimetric analysis (TGA). The sago cortex was found to have lower ash content as compared to other types whereas the mean calorific value of the briquettes were found to be 21.63 MJ/kg, 23.23 MJ/kg and 22.33 MJ/kg for sago barks, sago fronds and sago cortex, respectively. Experimental results showed that sago biomass is a potential alternative fuel for current fuels