Streptomyces viridosporus T7A and S. badius 252 were grown in 1 to 2% (wt/vol) slurry cultures with mineral salts solution containing 0.6% yeast extract and 100/200 mesh ground and extracted corn lignocellulose at 37°C. Enzyme activities rapidly increased in the first 3 to 4 days and then declined and remained at a relatively constant level. Concentrations of endoglucanase and xylanase produced by S. badius were lower than those produced by S. viridosporus. However, the lignin-peroxidase peak concentration was threefold higher than with S. viridosporus and was obtained at 9 to 10 days of incubation. By polyacrylamide gel analysis, it was determined that peroxidases from both species consisted of four enzymes, with only one, the lignin peroxidase, having high activity. A culture pH of 8.5 was preferable for lignocellulose degradation by S. badius.

The production of peroxidases by Streptomyces viridosporus T7A and recombinant Streptomyces lividans TK64.1 was characterized in stirred tank fermentors. The rate of peroxidase production was strongly growth associated with plasmid‐coded S. lividans, in contrast to chromosome‐coded S. viridosporus, where peroxidase production was proportional to cell mass rather than cell growth rate. A modified form of the logistic equation gave a good fit to the experimenal data for cell growth and peroxidase formation.

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In ammonia reactor system, a feed-effluent heat exchanger (FEHE) is typically installed to utilize reaction-generated heat to heat the reactor’s feed. Utilizing energy from exothermic reaction to the incoming feed stream is often called “autothermic operation”. Despite the advantage of FEHE, there is a risk of utilizing FEHE in a reactor system such as instability of process temperature or known as hysteresis. Hysteresis phenomena in chemical process could cause operational problems, for example it could damage the integrity of the equipment’s material. This paper aims to evaluate the dynamic behavior of a single-bed ammonia reactor with FEHE, particularly to propose a way to prevent instability within the system. The dynamic simulation of the single-bed ammonia reactor with FEHE was performed with Aspen HYSYS v8.8. The result of the simulation result shows that hysteresis phenomenon in the ammonia reactor system occurs when the feed’s temperature is below a certain value. If the feed temperature reaches that value, the temperature of the reactor’s outlet oscillates. One of the solution to keep the feed temperature above that critical value is by installing a trim heater within the system. Based on the simulation, trim heater installation within the system is able to prevent hysteresis in the system evaluated.

Iron chelate liquid redox sulfur recovery (LRSR) has been one of the most frequently recommended technologies for the oxidation of H 2 S in natural gas into elemental sulfur, particularly when the acid gas has a high CO 2 /H 2 S molar ratio. The process is however known to suffer from extensive oxidative ligand degradation that results in high operational costs. Moreover, poor biodegradability or toxicity of the existing ligand has become a concern. In this research, we demonstrated that gluconate, a naturally greener ligand, when coupled with manganese as the metal, has considerable potential to be a better redox agent. Manganese gluconate solution was more resistant against ligand degradation compared with iron NTA. As required, aerated solution was capable of converting dissolved NaHS into elemental sulfur. At sufficiently high pH, manganese gluconate solutions were stable enough from precipitation of manganese hydroxide, carbonate, or sulfides. An equilibrium calculation has been developed to understand the precipitation behavior.