Butanol and ethanol production from tapioca starch wastewater by Clostridium spp

Total (TWW) and tapioca starch wash wastewater (TSWW) from a cassava processing plant in Thailand were analyzed for their composition with a view to evaluate their potential as substrates for solvent production by ABE fermentation with Clostridium spp. Starch was detected at a 1.63-fold higher level in the TWW than that in the TSWW (24.4% and 15.0% (w/w), respectively). The chemical oxygen demand (COD) was broadly similar (20,093 and 20,433 mg/L), but the biological oxygen demand (BOD) was 1.84-fold higher (18,000 and 9,750 mg/L) in the TWW than that in the TSWW. Thus, the TSWW was selected as a substrate to evaluate its potential for butanol and ethanol production by two Clostridium spp. The combined ethanol plus butanol production in the TSWW at pH 6.5 was higher than that at pH 4.5, being around 27.8- and 3.4-fold higher in C. butyricum TISTR 1032 and C. acetobutylicum ATCC 824, respectively. In both strains, the butanol (and combined butanol plus ethanol) production level was improved at pH 5.5. The addition of yeast extract increased the bacterial cell production, but did not significantly improve solvent productivity in C. acetobutylicum, and even decreased butanol production by C. butyricum.     

Using Corn Husk Powder as a Novel Substrate to Produce a Surface Active Compound from Labrenzia aggregate KP‐5

In this study, surface active compound (SAC)‐producing bacterial isolates were evaluated for SAC production using corn husk powder (CHP) as a sole carbon source. From the 51 isolates screened, Labrenzia aggregate KP‐5 produced the highest SAC activity. The highest SAC production (3.51 g L^?1) was obtained when the strain was cultivated in a minimal salt medium containing 40 g L^?1 CHP and 1 g L^?1 commercial monosodium glutamate at 30 °C and 150 rpm after 51 h of cultivation. The produced SAC had the ability to decrease the surface tension of water from 72.0 to 25.5 mN m^?1, with the critical micelle concentration of 9 mg L^?1 (11.07 mM) and exhibited the highest emulsification activity (EA) of 81% against motor oil. The SAC showed stability at 4–121 °C and pH 4–10 against the surface and EA of vegetable oils and hydrocarbons, and showed tolerance at high salt concentrations (1–10% NaCl). The chemical structure of the SAC was confirmed as a rhamnolipid using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and mass spectrometric analysis. The SAC did not exhibit inhibitory effects on various vegetables tested; however, strong inhibitory activity against Gram‐positive and Gram‐negative bacteria was observed. The application of SAC for microbial enhanced oil recovery by sand saturated with used lubricating oil resulted in above 89% of oil removal. The properties of the SAC we obtained from CHP have potential applications especially for microbial enhanced oil recovery and/or reducing the intensity of environmental contamination. In addition, the obtained SAC is a suitable alternative to antimicrobial agents.     

Collecting Metrics for CORBA-Based Distributed Systems

The Common Object Request Broker Architecture (CORBA) supports the creation of distributed systems that cross processor, language and paradigm boundaries. These systems can be large and complex entities that consume considerable resources in their creation and execution. Measurements of characteristics of software systems is an important area of study in general and of particular interest for distributed systems. In this paper, we present a specific technique for instrumenting components in a distributed system. The technique constructs a wrapper around the component being measured. The wrapper monitors interactions with the ORB (Object Request Broker) and other components. Each wrapper mimics the interface of the component that it is wrapping so that the remaining objects in the system do not need modification. Two approaches to wrapping the component are presented and contrasted. The result is an efficient and modular technique that can quickly be applied to a component.