Algal biomass and its commercial utilisation

Algal biomass is a source of high value products worth over A$100 x 10 6 per annum. Red and brown seaweeds yield the phycocolloids, which are used as gelling, viscosity and clarifying agents in the food, cosmetic and pharmaceutical industries. Microalgal products in the health food market include Spirulina and Chlorella powder and tablets. The blue phycocyanin pigment extracted from Spirulina is used as a food colouring, and P-carotene extracted from Dunaliella salina, is sold as a yellow food colouring, and for its provitamin A and anti-oxidant properties in nutritional supplements. Development of new intensive culture systems is expected to widen the range of commercial algal products in the future

Limits to growth and carotenogenesis in laboratory and large-scale outdoor cultures of Dunaliella salina

Non-axenic laboratory cultures and mixed-species microcosms were used to assess the limiting factors to growth and carotenogenesis in the halophilic green alga Dunaliella salina. Growth is inhibited at low temperatures, especially night-time temperatures. N03 is the best form of N, while NH4N0 3 leads to cell death. Fe-citrate is the best form of Fe for growth. In .order to control protozoan predation cultures must be grown at salinities >17% NaCl (w/v) with 20% NaCl being optimal for growth and carotenoid content. Adequate nutrients must also be supplied

The Reverend Dr Louis Giustiniani and Anglican conflict in the Swan River Colony, Western Australia 1836-1838*

In 1835, the Western Australian Missionary Society appointed the Reverend Dr Louis Giustiniani to establish a Moravian-style mission in the Swan River Colony. The land grant essential for such a mission was not forthcoming from the government but Giustiniani established a small mission farm employing Aborigines at Guildford and started ministry among the settlers. This change of mission focus set the stage for conflict within the Anglican establishment of the colony, conflict which destroyed Dr Giustiniani's ministry. Giustiniani was well qualified and exerted himself to achieve the mission's objectives and many accusations made against him were essentially false; they reveal much about the prevailing culture and prejudices of the colony. He was defeated, however, because his ideas of church and mission differed from those of the colonial Church and society and because he did not conform to their expectations of the behaviour of a clergyman

A preliminary study of algal turf communities of a shallow coral reef lagoon using an artificial substratum

The growth, productivity and species composition of algal turf communities growing on glass microscope slides at various sites in the lagoon of One Tree Island,Capricorn Group, Great Barrier Reef, Australia (23° 30′ S, 152° 06′ E) were measured, and the possible use of algal communities growing on artificial substrates for ecological studies was assessed. Colonization of the bare glass slides by bacteria, green and blue-green algae was rapid. After 3 months, the slides had become covered by filamentous and crustose algae [e.g. Sphacelaria tribuloides Meneghini, Herposiphonia tenella (C. Agardh) Naegeli, Tenarea sp. etc.] and invertebrates (e.g. Spirorbis sp.). Crustose coralline algae settled evenly over the surface of the slide but were soon removed from the slide centre by grazing fish. Eventually, thicker crustose corallines [e.g. Porolithon onkodes (Heydrich) Foslie] from the less grazed edges of these slides began to overgrow the slides, providing a different substrate for growth of algal species such as Lophosiphonia spp. and Laurencia papillosa (Forsskål) Greville, etc. Various differences in species composition were observed between the different sites and depths. In general, the glass slide communities were less diverse than those on nearby natural substrates, presumably due to the hardness of the glass slides

Effects of salinity increase on carotenoid accumulation in the green alga Dunaliella salina

The effect of sudden salinity increases on the kinetics of growth and carotenogenesis was studied in three geographically diverse isolates of Dunaliella saliva. A sudden increase in salinity results in a lag phase in growth and the length of this lag phase is dependent on the final salinity and the magnitude of the salinity change (no lag at 10-15% w/v NaCl, 4-day lag at 30% NaCl). There is also a lag before an increase in the total carotenoid content can be measured following the salinity up-shock, and the length of the lag depends largely on the initial salinity and the magnitude of the salinity up-shock, whereas the rate of carotenogenesis and the final carotenoid content reached depend on the final salinity. The increase in total carotenoid content is mainly due to β-carotene. Following the salinity up-shock (especially from 10% to 20% NaCl) the proportion of lutein as a percentage of total carotenoids decreases, whereas zeaxanthin increases. This suggests that the pathway synthesising lutein is more sensitive to salt or osmotic stress and is inhibited at higher salinities, thus leading to β-carotene formation. The proportion of α-carotene does not change

The protozoa of a Western Australian hypersaline lagoon

Hutt Lagoon, 28° 11′S, 114° 15′E, 600 km north of Perth, Western Australia and lying 5 m below sea level is the site of a pilot plant erected by Roche Algal Biotechnology for growing and harvesting the alga Dunaliella salina. The lagoon is filled to a depth of 50–75 cm by rainfall (18% w/v salinity or above) during the winter months and is desiccated to a 5 cm or more thick crust during the summer. Salt from the crust used to prepare a growth medium for D. salinaintroduced a number of protozoa to the cultures, some of which made great inroads on the algal population. Most of the protozoa in the crust are presumed to be in the form of cysts and originate from more or less permanent seeps and pools (>5% w/v salinity) resulting from the inflow of water from the Indian Ocean on the west and from continental ground water on the east. The salt of the crust is thus a mixture of athalassic and thalassic origin. Only the lower reaches of the seeps are inundated by the winter water rise. Fourteen ciliates, 10 zooflagellates and 4 sarcodines were observed frequently enough in brines of over 15% (w/v) salinity to identify. At least one parasite of D. salina is included in the flagellate group. Although no concerted effort with the phytoflagellates was made, the rarely seen species D. peircei, D. jacobae and Ochromonas cosmopolitus were noted, as well as a Gymnodinium sp. The ciliates include the bacteriophagous Trachelocerca conifer, Metacystis truncata, Chilophrya utahensis, Rhopalophrya salina, Uronema marinum, Condylostoma sp. and Palmarella salina. Those eating both bacteria and algae were Nassula sp., Fabrea salina, Blepharisma halophila, Cladotricha sigmoidea, and Euplotes sp. Ciliates feeding on other ciliates include Podophrya sp. and Trematosoma bocqueti. Among the zooflagellates were several species of Monosiga, Rhynchomonas nasuta, Phyllomitus sp., Tetramitus salinus, T. cosmopolitus, Bodo caudatus, B. edax and 3 other distinctive Bodo species, one being parasitic on D. salina. All of the sarcodina fed on both algae and bacteria, except for the smallest amoeba (4 μm diameter rounded) which did not feed on algae, and included Heteramoeba sp. with both flagellate and amoeboid phases, an orange amoeba, an orange filopod-forming organism and a colorless filopod-forming organism, the last three of unknown genus. The relationship of these protozoa to the lagoon and to D. salina culturing is discussed