Experimental investigation on sucrose/alumina catalyst coated converter in gasoline engine exhaust gas.

In this study, a modified catalytic converter was employed to treat the harmful exhaust gas pollutants of a twin-cylinder, four-stroke spark-ignition engine. This research mainly focuses on the emission reduction of unburnt hydrocarbons, carbon monoxide, and nitrogen oxides at low light-off temperatures. A sucrolite catalyst (sucrolite) was coated over the metallic substrate present inside the catalytic converter, and exhaust gas was allowed to pass through it. A scanning electron microscope, X-ray diffraction, and Fourier transform infrared spectroscopy were used to investigate the changes in morphology, chemical compounds, and functional group elements caused by the reactions. Catalytic reactions were studied by varying the engine loads and bed temperatures, and the results were compared with those of the commercial catalytic converter. The results show that sucrose present in the catalyst was suitable at low temperatures while alumina was suitable for a wide range of temperatures. In the case of the modified catalytic converter, the maximum catalytic conversion efficiencies achieved for oxidizing CO and HC were 70.73% and 85.14%, respectively, and for reduction reaction at NOx was 60.22% which is around 42% higher than in commercial catalytic converter. As a result, this study claims that sucrolite catalyst is effective for low-temperature exhaust gas.

A novel low pH fermentation process for the production of acetate and propylene glycol from carbohydrate wastes.

A novel low pH fermentation process was studied for the conversion of lactose using Lactobacillus plantarum and Lactobacillus buchneri under anoxic conditions in single co-culture, and two-stage sequential fermentations. This is aimed at producing acetate and propylene glycol (PG) as environmentally benign substitutes for currently used road and aircraft deicing chemicals. The results indicate that in the case of two-stage fermentation with immobilized L. buchneri in the second stage, lactose degradation rate increased markedly producing acetate and PG concentrations of 12.1 and 10.7 g L-1 at pH 3.8. In the case of coculture fermentation, the acetate and PG concentrations were 8.2 and 6.8 g L-1, respectively. Fermentation of lactose and whey powder was conducted at pH 4.25 using a high cell density culture of L. buchneri. The acetate and PG yields were similar for both substrates at ∼0.3 g/g and ∼0.33 g/g respectively. With a starting lactose concentration of 60 g/L, acetate and PG concentrations of 18 g/L and 21 g/L respectively were obtained. The low pH conversion of wastes to value-added products under anoxic conditions provides substantial operating benefits over neutral pH fermentations that require strict anaerobic conditions for effective operation. Moreover, the low product pH at around 4.0 will provide substantial savings in downstream processing costs due to the much higher extraction efficiency of weak- and moderate- base resins for acetic acid compared to acetate ion.

Exploitation of acid-tolerant microbial species for the utilization of low-cost whey in the production of acetic acid and propylene glycol.

Whey from cheese and yoghurt production operations contains useful constituents such as whey protein and lactose. However, the separation and extraction processes are difficult and costly, and hence, whey has limited end user demand and is typically disposed of as waste. Treatment and disposal of these high BOD wastes are both energy intensive and expensive. However, improper disposal of these wastes can pollute surface and ground water resources. The use of these low or negative cost substrates for the production of value-added products such as acetic acid and propylene glycol (PG) is of great significance in changing overhead costs to revenue streams. The present study focuses on bioproduction of acetic acid and PG from whey lactose and whey powder containing lactose and protein as an alternative to high cost nutritive medium. It was found that Lactobacillus buchneri, an acid-tolerant bacterium, is able to ferment lactose at pH ~ 4.2 to low molecular weight compounds such as acetic acid and PG each at 25-30 g L-1 concentration when using lactose as a major carbon substrate. The typical molar ratio of acetic acid to PG was close to 1:1 at the end of fermentation. The productivity of acetic acid and PG was improved using a high cell density fermentation with cotton cheesecloth as an immobilization matrix. The use of whey powder with immobilized fermentation system showed a similar performance to that of cultures fed with pure lactose at pH 4.2, resulting in a 57% conversion of lactose in whey to acetate and PG in total, against a stoichiometric maximum of 72%.

Molecular analysis of sleep: wake cycles in Drosophila.

Sleep is controlled by two major regulatory systems: a circadian system that drives it with a 24-hour periodicity and a home-ostatic system that ensures that adequate amounts of sleep are obtained. We are using the fruit fly Drosophila melanogaster to understand both types of regulation. With respect to circadian control, we have identified molecular mechanisms that are critical for the generation of a clock. Our recent efforts have focused on the analysis of posttranslational mechanisms, specifically the action of different phosphatases that control the phosphorylation and thereby the stability and/or nuclear localization of circadian clock proteins period (PER) and timeless (TIM). Resetting the clock in response to light is also mediated through posttranslational events that target TIM for degradation by the proteasome pathway; a recently identified ubiquitin ligase, jet lag (JET), is required for this response. Our understanding of the homeostatic control of sleep is in its early stages. We have found that mushroom bodies, which are a site of synaptic plasticity in the fly brain, are important for the regulation of sleep. In addition, through analysis of genes expressed under different behavioral states, we have identified some that are up-regulated during sleep deprivation. Thus, the Drosophila model allows the use of cellular and molecular approaches that should ultimately lead to a better understanding of sleep biology.