Exopolysaccharide production by Lactobacillus confusus TISTR 1498 using coconut water as an alternative carbon source: the effect of peptone, yeast extract and beef extract

Coconut water (CW) is a by-product of food industry and has little value in Thailand. It is usually discarded as a wasteinto the environment. Consequently, we developed a value added process of exopolysaccharide (EPS) production usingLactobacillus confusus TISTR 1498 and coconut water. The effect of three expensive supplements (peptone, yeast extractand beef extract) on EPS and biomass production was investigated at 35°C for 24 h. Using a mod-MRS-CW medium, preparedby replacing the de-ionized water with 100% CW and supplemented with 20 g/l crystalline sucrose and a reduced quantity(50%) of the three expensive supplements (5 g/l of peptone, 2.5 g/l of yeast extract, and 2.5 g/l of beef extract) gave thehighest yield of EPS (12.3 g/l). By optimizing the conditions for fermentation (pH 5.5, agitation speed at 50 rpm and initialsucrose concentration of 100 g/l), EPS yield increased up to 38.2 g/l. When compared with the modified MRS medium, themedium supplemented with CW was found to be suitable for the reduction of cost spent on the organic nitrogen and growthfactors (savings close to 50%)

Isolation and characterization of thermotolerant bacterium utilizing ammonium and nitrate ions under aerobic conditions

好気条件下で、アンモニアと硝酸塩を同時に除去する耐熱性菌を分離した。本菌は30C及び50Cにおいて両窒素化合物を効率的に除した。また、それらの代謝経路を明らかにした

Using AMF inoculum to improve the nutritional status of Prunella vulgaris plants in green roof substrate during establishment

Arbuscular mycorrhizal fungi (AMF) have been shown to improve the growth, health, nutrient uptake, flowering and drought tolerance of many terrestrial plant species. Green roofs are generally deficient in nutrients, organic matter and water, and therefore AMF could be extremely beneficial in improving green roof plant performance. Despite this there is a lack of empirical research into artificially introducing AMF into green roof substrates. In this study, a commercial AMF inoculum was applied to Prunella vulgaris green roof plugs grown in small modules on a flat roof in Sheffield, UK. The modules were filled with commercial green roof substrate (80% small particle sized crushed brick, 20% green waste compost) to a depth of 100 mm. AMF inoculum was applied as four treatments: (i) directly with plug, (ii) mixed evenly into surrounding substrate, (iii) split between plug and substrate, (iv) control treatment with no inoculum added. Significantly greater levels of AMF colonisation of P. vulgaris roots was detected in all AMF treatments compared to the control. Low levels of AMF colonisation of P. vulgaris roots were also observed in the control treatment, confirming that low levels of AMF inoculum were present in this commercial substrate. Shoot phosphorous (P) concentration was improved in all AMF treatments, however there was no significant effect of any AMF treatment on P. vulgaris growth rate or biomass production. The highest AMF colonisation of P. vulgaris roots was observed when AMF inoculum was directly added to just the plug. Promisingly, P. vulgaris flowering time at the end of the first growing season was also extended in the plug AMF treatment only. This study has confirmed that commercial AMF inoculum can be used to successfully colonise plants and introduce AMF networks into green roof substrate. Although AMF inoculum was naturally present in the substrate used in this study, levels were extremely low, and unlikely to have any significant effect on plants. This study indicates that care should be taken in the use of AMF inoculum on green roofs, as the growth and health benefits of AMF are not always immediately apparent for green roof plants. In addition much more research is required in order to fully assess the extent of the benefits of AMF on green roof plants and to determine if their use can be financially viable

Pemahaman nilai-nilai pendidikan multikultural dalam upaya membangun keberagaman inklisif santri pada pesantren modern Datok Sulaeman

viii 132 ha

Effect of sodium chloride on cell surface hydrophobicity and formation of biofilm in membrane bioreactor

This work presents an experimental study aimed at assessing the relationship between cell surface hydrophobicity (CSH) and the formation of a membrane-attached biofilm. In particular, the investigation focused on the effects of growth conditions on the hydrophobicity of bacterial cells grown in suspension. Identical growth conditions were then used in a lab-scale extractive membrane bioreactor fed on phenol as the sole carbon source to assess their effect on biofilm formation. CSH was found to decrease with increasing cellular age and in the presence of sodium chloride (0.5% w/v) in the growth medium. Pictures taken by a digital camera clearly showed the differences in biofilm morphology resulting from the different growth conditions: biofilms formed in the membrane bioreactor under low CSH (2%) condition proved to be thinner and more fragile than those formed under high CSH condition (44%)

Effect of medium composition and system operation on membrane-attached biofilm morphology alteration and system performance in membrane bioreactor

The formation and accumulation of membrane-attached biofilm (MAB) in membrane processes can prove to be detrimental to process performance due to mass transfer limitation. This effect demands countermeasures to minimize its accumulation. In this research, the influence of medium composition and system operation on morphology alteration of MAB and consequently their influence on mass transfer rate and overall system performance was investigated in a lab - scale extractive membrane bioreactor used for the extraction and degradation of phenol. The factors investigated included dilution rate, ammonium concentration, iron concentration and phenol feed concentration. The continuous feed of the growth medium and the change in dilution rate produced thinner but stronger and more controllable biofilm than that observed in a semi-batch experiment. Washout of the suspended cells was achieved by increasing the dilution rate to a value of 0.03 h1 and from this moment on, visible cell growth occurred only within the biofilm. Complete absence of iron from the growth medium affected biofilm morphology whereas a decrease in ammonium concentration did not. However, in both cases phenol degradation efficiency was not affected. A feed concentration of 5 g/l resulted in large - scale detachment of biofilm but detached cells were well adapted to high phenol concentration environment and kept their ability to degrade transferred phenol. It is, therefore, concluded that this system is very robust to alteration in the nutrient feed and that once the biofilm is formed, alteration in its morphology and thickness did not have a significant effect on the system performance