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f o r each of the m a j o r subsystems: principally growth pond, harvesting and CO2 supply systems. supply to the ponds was carried out. Processing was only addressed cursorily. Operating costs (labor, electrical and nutrients) were also estimated. Four different cases of C 0 2 supply were cost estimated: recycle at high pH and no recycle at low pH. The cost of flue gas transport and transfer about equaled the projected costs of commercial CO , at CZ/pound. A cost routine was developed to convert t 2 e cost estimates to total product COS~SS. Capital and operating cost factors used for engineering, contractors fees, contingencies, insurance, maintenance, etc. were similar to those used on other DOE studies. Other factors used included land costs, labor and utility unit costs, overhead, and working capital. A return on investment (ROI, before ta#es) of 15% was used to calculate total product costs. capital charges and factors were 71% of total product costs. An engineering design and cost estimate was carried out A detailed analysis of COZ flue gas and pure C 0 2 , each with CAt that ROI, ii Total costs were estimated at about $125/barrel of o i l for the C recycle cases (pure C02 or flue gas); the higher costs of the nonrecycle case ($150/barrel) would likely be offset by the value of any byproducts. carried out to evaluate the effect on estimated costs by reduction of key cost elements. reduction of about 25%, on average, of capital and operating costs, and a similar reduction in the cost factors, resulted in an overall cost reduction to as low as $60/barrel of oil. This required the onsite use of coal for supplying (202. Higher productivities would lower costs further, but they cannot be forecast based on existing knowledge. Other options, such as methane or alcohol production or use of seawater as a water and carbon source have similar costs. In conclusion, even with optimistic projections,microalgae liquid-fuel costs are about twice those of current prices. biomass systems were explored. exist, principally wastewater treatment and specialty chemicals and feed production, the market potential of these byproducts is limited in terms of total energy production. e A sensitivity analysis was An optimistic, but still reasonable, c Alternative byproducts from microalgae Although a number of options 0 8 3 8 a Issues that must be addressed are the technical feasibility of the proposed fuel-production processes and the potential contributions to U.S. fuel supplies. The former requires research, ofabasic and applied nature, in the area of microal-gae physiology and population dynamics in open systems. involves an assessment of the key resourcescarbon overlap.

SummaryThis study reports some findings on the death of mammalian cells occurring from fluid dynamic effects when they are pumped through capillaries. The cell strains used were human HeLa 53 and mouse L929, grown in monolayer culture.Cells were harvested and suspensions were pumped through various lengths and diameters of stainless steel capillary tubing. Viability of the cells w&s assayed by the dye exclusion test. Cell deaths occurred and could be correlated with either average wall shear or power dissipation within the capillary tube. L929 cells were found to be more sensitive than HeLa S3 cells a t all shear rates tested.

SummaryStudies to examine the microbial fermentation of coal gasification products (COs, H, and CO) to methane have been done with a mixed culture of anaerobic bacteria selected from an anaerobic sewage digestor. The specific rate of methane production at 37°C reached 25 mmoVg cell hr. The stoichiometry for methane production was 4 mmol H,imol CO,. Cell recycle was used to increase the cell concentration from 2.5 to 8.3 g/liter: the volumetric rate of methane production ran from 1.3 to 4 literiliter hr. The biogasification was also examined at elevated pressure (450 psi) and temperature to facilitate interfacing with a coal gasifier. At 60"C, the specific rate of methane production reached SO mmol/g cell hr. Carbon monoxide utilization by the mixed culture of anaerobes and by a Rhodopserrdomonrrs species was examined. Both cultures are able to carry out the shift conversion of CO and water to C 0 2 and hydrogen.

SummaryA high molecular weight intracellular enzyme of Bacillus brevis ATCC 9999 is released when the organism is disrupted by sonication of homogenization. However, both processes also degrade the enzyme. Assays for protein release and specific enzymatic activity of the released protein indicate that both release and degradation can be represented by first-order kinetic models. Utilization of the difference between the kinetics of release and degradation allows optimization in t,he recovery of this enzyme for both the sonication and homogenization processes.

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