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The applicability of ionic liquid-methanol cosolvent system to both extract bio-oil and simultaneously pretreat the carbohydrate fraction of jatropha and safflower biomass for enzymatic hydrolysis to fermentable sugars is presented. Although pretreatment with either the cosolvent or pure ionic liquid yielded comparable hydrolysis kinetics and fermentable sugar yields on safflower whole seeds, the addition of alcohol to the ionic liquid was necessary to optimally recover both bio-oil and fermentable sugars. The ionic liquid [C2mim][Ac] was far more effective than [C2mim][MeSO4] with optimum processing conditions occurring at a cosolvent concentration of 70–30 wt% of [C2mim][Ac] to methanol and a processing temperature of 120°C. Under these conditions, the majority of the bio-oil was extracted and 25.4 wt% (safflower) and 14.3 wt% (jatropha) of the whole seed biomass were recovered as fermentable sugars. The recovery of fermentable sugars from the carbohydrate fraction was as high as 74% and 78% for jatropha and safflower seeds, respectively, when using [C2mim][Ac] cosolvent. A preliminary theoretical analysis of two potential oil seed processing pathways using the cosolvent system suggested that the corecovery of bio-oil, fermentable sugars, and a protein rich meal can recover a majority of the energy contained in the original biomass—a result that improves upon the traditional approach of solely extracting bio-oil.

Although current production in response to a polypyrrole (PPy) surface interaction with ammonia has been exploited in different sensor configurations, the origin of current generation has yet to be characterized. One of the standing issues critical to the use of this PPy–ammonia current generation is the limited lifetime of the PPy in the presence of ammonia. Our investigations into a possible mechanism for this reaction and experimental results indicate that this current generation is significantly more sustainable in the presence of a reactive oxygen species. Increase in lifetime (up to 50 fold) for such current generation has allowed an investigation of the reaction at different ammonia concentrations and pHs. Such experimentation allows the further contemplation of the use of ammonia as a possible fuel in a room temperature and ambient pressure fuel cell without an anodic precious metal catalyst. [ABSTRACT FROM AUTHOR]

A starvation-based dissolved oxygen (DO) transient controller was developed to supply growth-limiting substrate to high cell density fed-batch cultures of recombinant Escherichia coli. The algorithm adjusted a preexisting feed rate in proportion to the culture's oxygen demand, which was estimated from transients in the DO concentration after short periods of feed interruption. In this manner, the addition of glucose feed was precisely controlled at a rate that did not exceed the acetate production threshold, thus preventing acetate accumulation. In comparison to exponential feed algorithms commonly used in industry, the implementation of the new feeding strategy increased the final cell density from 32 to 44 g (dry cell weight).L-1, with less than 16 mM acetate accumulated, producing an ideal culture for subsequent induction. Despite a constant starvation level and relatively low levels of acetate, experimental cultivations still tended to produce acetate towards the end of the process. The use of a simple Monod model provided an explanation as to why this may occur in high cell density cultivations and suggests how it may be overcome. © 2004 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

DO-transient nutrient controllers use the dissolved oxygen signal to attempt acetate threshold tracking during fed-batch cultivation of recombinant E. coli. Here we apply DO-transient control to the production of Jembrana disease virus protein in complex Super Luria medium and compare performance against a high-limit pH-stat controller. For induction at medium cell density (harvest between 31 and 32.5 g dcw L) a total productivity of 0.27 g L h was achieved as compared to 0.24 g L h with the high-limit pH-stat. For induction at high cell density (harvest at 60 g dcw L), decreased productivity (0.12 g L h) was attributed to the effect of acetate accumulation on recombinant protein formation and a concomitant lowering of the critical growth rate. Our results suggest that complex media provides a difficult environment for the application of acetate threshold tracking DO-transient control because of difficulties in re-oxidizing acetate, and apparent localized production of acetate below the production threshold (as detected by the DO-transient controller as SPOURcrit). Configuring the DO-transient controller to avoid aggressive threshold probing is suggested as a means to improve performance and reduce acetate accumulation in complex media. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 84: 314–323, 2003. [ABSTRACT FROM AUTHOR]