C, N, P, S content of the Chlorophyta Chaetomorpha linum (Müller) Kützing in a vast high density mat of a Mediterranean non-tidal lagoon

In a Chaetomorpha linum high density mat extending over 300 hectares, between 2017 and 2019 samples were collected for C, N, P, S tissue content determination, biomass (b) was estimated, sediment samples collected for labile organic matter (LOM) determination, and water chemical-physical variables measured. The latter showed extreme conditions with a wide range of values ​​and with zero oxygen for long periods. N-NO3:SRP atomic ratio showed extreme P-limitation. Tissue macronutrients showed very variable values, highlighting a strong P-limitation and relatively high level of S. With exception of nitrogen, no significant differences were detected for each macronutrient between the months and between the stations, neither was any correlation found between macronutrients and LOM and b data-set. The growth and survival of the mat occurred despite the scarcity of P, which probably reached with very low frequency the surface layer of the mat, the one capable of performing photosynthesis, where it was quickly re-assimilated and utilised.

Integrated Multitrophic Aquaculture By-Products with Added Value: The Polychaete Sabella spallanzanii and the Seaweed Chaetomorpha linum as Potential Dietary Ingredients

Aquaculture expansion is limited by the negative environmental impact of the waste and the need for alternative sources in the diet of reared fish. In this framework, for the first time, the survival rates, biomass gain, and fatty acid profiles of the polychaete Sabella spallanzanii and the macroalga Chaetomorpha linum, reared/cultivated as bioremediators in an integrated multitrophic aquaculture system (IMTA), were evaluated for their potential reuse applications. Results showed that these organisms represent a natural source of omega-3 and omega-6. On account of the overall results and the high biomass obtained as by-products, a preliminary study was performed employing both S. spallanzanii and C. linum as new dietary ingredients to feed different sized Dicentrarchus labrax. Fish survival rate, biomass growth, and specific growth rate were determined resulting in no significant differences between control and treated fishes. Histological analyses showed no alterations of the stomach tunica mucosa and submucosa in treated fishes. The eco-friendly approaches applied in the here-realized IMTA system could guarantee the achievement of sustainable by-products represented by the bioremediators S. spallanzanii and C. linum, as well as their reliability as a natural source of compounds beneficial to fish and human health.

Characterization and Analysis of Malaysian Macroalgae Biomass as Potential Feedstock for Bio-Oil Production

The potential of Caulerpa lentillifera, Gracilaria coronopifolia and Chaetomorpha linum, as biomass feedstock was investigated in this study. It was concluded that seaweed is more suitable for bio-based products synthesis, i.e., bioplastic and bio-lubricants, instead of biofuels due to its relatively low calorific value (~12 MJ/kg). Since seaweed has high moisture content (~80%), hydrothermal liquefaction is recommended, and its efficiency can be further enhanced through microwave technology. Besides, it is found that the thermal degradation of seaweed was best described with the reaction order of 1. The kinetic results also indicated that seaweed consists of lower activation energy (<30 kJ/mol) in comparison with terrestrial biomass (50–170 kJ/mol). Hence, seaweed has a high potential to be used as biomass feedstock, particularly Chaetomorpha linum, as it has no conflict with other interests. Lastly, acetic-acid pre-treatment was suggested to be an optional process in order to increase the algal conversion efficiency as it can reduce up to 25% of ash content.

Production of Biodiesel from Marine Macroalgae occurring in the Gulf of Guinea, off the Coast of Ghana

The purpose of this study was to determine the suitability of marine macroalgae (also known as seaweeds), from the Gulf of Guinea, off the coast of Ghana, for the production of biodiesel as an alternative to liquid fuels like gasoil and gasoline. Five green marine macroalgae species: Caulerpa taxifolia, Chaetomorpha antennina, Chaetomorpha linum, Ulva fasciata, and Ulva flexuosa, were collected from the coastal waters of Ghana at West Tema Rocks during low tide. Algal lipids were extracted from dried algae biomass with hexane and diethyl ether. Biodiesel was produced from algal lipids by base-catalysed transesterification, with alcohol. The lipid content of samples was highest in C. linum (1.13 g; 5.65% dry wt.) and lowest in C. antennina (0.54 g; 2.70% dry wt.). Similarly, the quantity of biodiesel produced from the lipids was highest in C. linum (0.97 g; 4.85% dry wt.) and lowest in C. antennina (0.48 g; 2.40% dry wt.). The quantity of biodiesel produced from samples of the five species fell well within the range obtained for such species worldwide. The implications of the yield of biodiesel for commercial production and future work on marine macroalgae from Ghana as source of biofuel are discussed.