Esther K. Nemethy

ANALYSIS OF EXTRACTABLES FROM ONE EUPHORBIA

Chemical analyses have been made of the heptane extractable material ofEuphorbia lathyris, a plant which has been proposed as an “energy farm” candidate. The heptane extract is 4–5% of the dry plant weight and has a heat value of ≈18×103 BTU/Ib. This reduced photosynthetic material consists almost entirely of polycyclic triterpenoids.

Biosynthesis of unusual acyclic isoprenoids in the Alga Botryococcus braunii

A ‘resting state’ isolate of the hydrocarbon-producing alga Botryococcus braunii photoassimilated sodium [14C]bicarbonate at rates comparable to fast growing algae, such as Chlorella (> 1.50 μg atoms 14C/mg chlorophyll·hr). Early in the reaction (up to several min), most of the radioactivity was associated with water-soluble metabolites. However, labelling of hexane-soluble compounds steadily from ca 3% at 15 sec to over 50% of the total incorporated 14C at 60 min. The purified hexane fraction, which consisted of a series of botryococcenes and squalene, constituted a relatively constant proportion (40–45%) of the total hexane-soluble radioactivity at all but the earliest time points (< 60 sec). This fraction initially consisted almost exclusively of a C30 botryococcene (ca 91%) and squalene (ca 8%); however, small amounts of radioactivity sequentially appeared in the C31, C32 and C34 botryococcenes. The results of pulse-chase experiments implicated the C30 botryococcene as the precursor of the higher homologues; during the chase, loss of radioactivity from the C30 compound was accompanied by a concomitant increase in the labelling of the C31 and C32 compounds. This study provides further evidence that the relatively slow growth of Botryococcus in culture may result, in part, from the diversion of a large proportion of reduced carbon into energetically expensive compounds and that the slower growth rate in the ‘resting state’ cannot be totally attributed to an impaired or intrinsically slow metabolism.

Plants as a direct source of fuel

Euphorbia lathyris, a plant which has been proposed as an ‘energy farm’ candidate yields a total of 35% of its dry weight as simple organic extractables. Chemical analyses of the extracts show that 5% of the dry weight is a mixture of reduced terpenoids, in the form of triterpenoids, and 20% of the dry weight is simple sugars in the form of hexoses. The terpenoids can be converted to a gasoline-like substance and the sugars can be fermented to alcohol. Based on a biomass yield of about 25 dry tons ha−1 year−1, the total energy that can be obtained from this plant in the form of liquid fuels is 48 MJ ha−1 year−1, 26 MJ in the form of hydrocarbons and 22 MJ in the form of ethanol. A conceptual process study for the large scale recovery ofEuphorbia lathyris products indicates that this crop is a net energy producer. Several lines of investigation have been started to increase the hydrocarbon yield of this plant. Tissue cultures ofE. lathyris have been established and will be used for selection, with the aim of regenerating a superior plant. Biochemical studies have been initiated to elucidate regulation of terpenoid metabolism. Future plans include eventual genetic engineering to select the most desirable plant for hydrocarbon production.

Terpenes from pittosporaceae

Abstract The monoterpenes of the fruits of Pittosporum resiniferum and P. undulatum have been identified. The essential oil of P. resiniferum contai

Lignans of Myristica otoba

Abstract The neutral fraction of the oil of Myristica otoba fruits afforded a series of seven lignans ofthe aryltetralin type.

TESTING FOR TUMOR PROMOTERS IN EUPHORBIA IATHYRIS: ANALYSIS OF POSSIBLE HEALTH HAZARDS

A sensitive test system for the detection of unknown tumor promoters is reported. A description is given of the use of the system in detecting promoter activity in Euphorbia lathyris extracts before and after treatment with organic solvents in the preparation of synthetic fuels. Using both normal and ts-virus infected cells, tumor promoter-like activities were detected and identified as ingenol esters in the active fraction of the latex of E. lathyris. These activities were shown to be inactive after extraction of potential sources of fuel. Results indicate that there should be no toxicological dangers after mechanical harvesting and drying. This finding has much potential significance, both for the further processing of E. lathyris and for other possible sources of energy. (JMT)