Daniel B. Anderson

Expression of Acidothermus cellulolyticus endoglucanase E1 in transgenic tobacco: biochemical characteristics and physiological effects

The expression of the Acidothermus cellulolyticus endoglucanase E1 gene in transgenic tobacco (Nicotiana tabacum) was examined in this study, where E1 coding sequence was transcribed under the control of a leaf specific Rubisco small subunit promoter (tomato RbcS-3C). Targeting the E1 protein to the chloroplast was established using a chloroplast transit peptide of Rubisco small subunit protein (tomato RbcS-2A) and confirmed by immunocytochemistry. The E1 produced in transgenic tobacco plants was found to be biologically active, and to accumulate in leaves at levels of up to 1.35% of total soluble protein. Optimum temperature and pH for E1 enzyme activity in leaf extracts were 81°C and 5.25, respectively. E1 activity remained constant on a gram fresh leaf weight basis, but dramatically increased on a total leaf soluble protein basis as leaves aged, or when leaf discs were dehydrated. E1 protein in old leaves, or after 5h dehydration, was partially degraded although E1 activity remained constant. Transgenic plants exhibited normal growth and developmental characteristics with photosynthetic rates similar to those of untransformed SR1 tobacco plants. Results from these biochemical and physiological analyses suggest that the chloroplast is a suitable cellular compartment for accumulation of the hydrolytic E1 enzyme.

Process Design and Economics for the Conversion of Algal Biomass to Hydrocarbons: Whole Algae Hydrothermal Liquefaction and Upgrading

This report provides a preliminary analysis of the costs associated with converting whole wet algal biomass into primarily diesel fuel. Hydrothermal liquefaction converts the whole algae into an oil that is then hydrotreated and distilled. The secondary aqueous product containing significant organic material is converted to a medium btu gas via catalytic hydrothermal gasification.

In Situ Bioremediation of Carbon Tetrachloride: Field Test Results

Abstract Results of a 7-month field test of in situ bioremediation of carbon tetrachloride (CT) under denitrifying conditions are reported. The demonstration was conducted in a portion of a several-square-mile CT and nitrate plume. Pretest CT and nitrate levels were 12.5 ± 0.14 μM and 3.87 ± 0.26 mM, respectively. During the test, the CT concentration dropped by 3.71 ± μM, representing an estimated total of 1.42 kg of CT destroyed. The total quantities of acetate and nitrate injected during the demonstration were 221 and 300 kg, respectively. Nitra injection was composed of short-duration, high-concentration pulses added with acetate pulses, and continuously injected nitrate that was present in the surrounding groundwater. Biomass was distributed successfully within the flow field without fouling the injection well. Levels of planktonic denitrifiers increased 10- and 5-fold in monitoring wells 3 and 6 m downstream from the injection well, respectively. A distributed growth pattern was indicated through re...

Whole Algae Hydrothermal Liquefaction: 2014 State of Technology

This report describes the base case yields and operating conditions for converting whole microalgae via hydrothermal liquefaction and upgrading to liquid fuels. This serves as the basis against which future technical improvements will be measured.