Microalgal growth and fatty acid productivity on recovered nutrients from hydrothermal gasification of Acutodesmus obliquus

Hydrothermal processing of microalgal biomass: Circular bio-economy perspectives for addressing food-water-energy nexus

Hydrothermal processing of microalgae is regarded as a promising technology to generate multitude of energy based and value-added products. The niche of hydrothermal technologies is still under infancy in terms of the technical discrepancies related to research and development. Thus, the present review critically surveyed the recent advancements linked to the influencing factors governing the algal hydrothermal processing in terms of the product yield and quality. The sustainability of hydrothermal technologies as a standalone method and in broader aspects of circular bio-based economy for energy and value-added platform chemicals are comprehensively discussed. Process optimization and strategic integration of technologies has been suggested to improve efficiency, with reduced energy usage and environmental impacts for addressing the energy-food-water supply chains. Within the wider economic transition and sustainability debate, the knowledge gaps identified and the research hotspots fostering future perspective solutions proposed herewith would facilitate its real-time implementation.

Influence of hydraulic retention time and carbon loading rate on the production of algae

This paper is focused on the assessment of the production of algae in batch bioreactors. Hydraulic retention time, carbon loading rate and light color were the inputs of the study and algae production the main output. Bioreactors were operated in semi-continuous mode and tests lasted two months, more than two times the period required to meet a steady-state response. This steady-state was verified with plateau responses in both, soluble parameters and suspended solids. Results points out the great relevance of temperature. Likewise, they show that green light improves the production of algae, as well as long HRT and high CLR. Maximum production rates attained were in the range 4-14 mg d^-1 L^-1. The ratio COD /TSS for this biofuel was almost constant (3.13 mg COD mg^-1 TSS) but the quality of the product obtained in terms of the Mean Oxidation State of Carbon is completely different. Longer HRT leads to lower MOSC and hence to potentially more valuable fuels.