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Extracting titanium from ilmenite ore (FeTiO3) by using the conventional methods require usage of hash chemicals and excessive heating, which are not environmentally friendly. Iron oxides are the most common impurities contained in ilmenite ores. Separating iron impurities from ilmenite ore remains as a challenging part in titanium extraction proses. In this study, we explored the application of iron-reducing bacterium, Shewanella oneidensis MR-1 to leach out iron from ilmenite ore. S. oneidensis MR-1 is known for its capability to reduce various metal oxides during anaerobic respiration. Reduction of iron oxides contained in ilmenite ore by respiration activity of S. oneidensis MR-1 transform insoluble iron(III) to soluble iron(II), which can leach out from the ilmenite ore. Different concentrations of ilmenite were incubated with S. oneidensis MR-1 under anaerobic conditions for 30 days. Reductive dissolutions of iron(III) from ilmenite ore were determined by monitoring iron(II) accumulation in the growth media every 3-4 days. Transformations of ilmenite ore after 23 days of S. oneidensis MR-1 treatment were further analysis by X-Ray diffraction (XRD) analysis. Incubation of S. oneidensis MR-1 with 0.10 g/ml of ilmenite ore showed the highest iron(III) reductive dissolution activity, with 1.4mM of iron(II) was leached out from ilmenite ore after 23 days. The XRD analyses indicated chemical composition and structural changes in the ilmenite incubated with S. oneidensis MR-1. The findings of this study show that reductive dissolution of iron(III) by S. oneidensis MR-1 is a promising environmentally friendly and inexpensive bioleaching strategy in removing iron impurities from ilmenite. [ABSTRACT FROM AUTHOR]

Ripened coconut water is a by-product of food industry in Southeast Asia countries including Malaysia. It is usually drained as effluent from the coconut processing factory into the environment which might cause pollutions. The aim of this study is to investigate the suitability of underutilized ripened coconut water as low cost carbon source for curdlan production by Agrobacterium sp. ATCC31749. Instead of ripened coconut water, un-ripened coconut water was also used as a carbon source in the fermentation medium of Agrobacterium sp. ATCC31749, under similar fermentation conditions such as initial pH and incubation times. Seed culture of Agrobacterium sp. ATCC31749 strain was initially grown in Luria-Bertani (LB) medium before been transferred into 2L flask containing the fermentation medium supplemented with coconut water. The incubation was conducted at 30 °C for seven days. Optical density (OD) measured by UV spectrophotometer showed that coconut waters as the carbon source supported the growth of Agrobacterium sp. ATCC 31749. Curdlan production by Agrobacterium sp. ATCC31749 was comparatively higher (10.831 mg/mL) with un-ripened coconut as the carbon source compared to ripened coconut water that yielded 9.546 mg/mL of curdlan. The result indicated that both un-ripened and ripened coconut water are suitable to be used as the carbon source for curdlan production by Agrobacterium sp. ATCC 31749.This study revealed how coconut water as the by-product waste in the food industry can be applied as substance for the production of value-added product. [ABSTRACT FROM AUTHOR]

Oil palm is a major commodity crop in Malaysia. Palm pressed fibers (PPF) is one of the major wastes generated during palm oil processing. Due to the large volume of waste generated each year, managing palm oil processing waste such as PPF remains as a challenging task in producing environmentally sustainable palm oil. Studies indicated that the application of microorganism can reduce the oil palm waste safely and cost effectively. This study aims to evaluate the degradation of PPF by model iron-reducing bacteria (IRB) strain, Shewanella oneidensis MR-1 and three locally isolated IRB strains, namely SG30, SG29 and KP20, via microbial driven Fenton reaction. With the present of oxygen, IRB undergo aerobic respiration to generate hydrogen peroxide (H2O2), while under anaerobic growth condition with Hydrous Ferric Oxide (HFO) was supplied as the sole electron acceptor, IRB reduce ferric iron (Fe3+) to ferrous iron (Fe2+). Fenton reaction between H2O2 and Fe2+ generated by IRB during aerobic and anaerobic respiration respectively, produced hydroxyl radicals that degrade PPF. The results show that after 7 days of incubation PPF degradation via Fenton reaction was greatest by S. oneidensis MR-1 (22.06 % dry weight) followed by SG30 (16.23%), SG29 (12.53%), and KP20 (9.13%), while abiotic control for the same experimental set up showed 2.61% of PPF compared to the three locally isolated IRB strains. Overall, this research potential application of microbial Fenton reaction to degrade PPF waste into more simple structure for downstream processing of PPF into useful products. [ABSTRACT FROM AUTHOR]