Microalgae dewatering is a major obstruction to industrial-scale processing of microalgae for biofuel prodn. The dil. nature of harvested microalgal cultures creates a huge operational cost during dewatering, thereby, rendering algae-based fuels less economically attractive. Currently there is no superior method of dewatering microalgae. A technique that may result in a greater algal biomass may have drawbacks such as a high capital cost or high energy consumption. The choice of which harvesting technique to apply will depend on the species of microalgae and the final product desired. Algal properties such as a large cell size and the capability of the microalgae to autoflocculate can simplify the dewatering process. This article reviews and addresses the various technologies currently used for dewatering microalgal cultures along with a comparative study of the performances of the different technologies.

Dewatering of microalgal cultures : a major bottleneck to algae-based fuels

Flocculation as a low-cost method for harvesting microalgae for bulk biomass production.

Volatile oil price and growing emphasis on environmental conservation have stimulated the development and utilisation of biomass as a vital source of renewable energy. In reducing the global dependency on fossil fuels, rice husk and rice straw which are the widely abundant agricultural wastes from the rice industry have a vital role to play. This paper reviews the key aspects of the utilisation of rice husk and rice straw as important sources of renewable energy. The paper provides some essential background information that includes the physical and chemical characteristics that dictates the quality of these rice biomasses. This paper also describes the various chemical and physical pretreatment techniques that can facilitate handling and transportation of rice straw and husk. Finally, the paper presents the state-of-the-art on thermo-chemical and bio-chemical technologies to convert rice husk and rice straw into energy.

A review on utilisation of biomass from rice industry as a source of renewable energy

Methods of downstream processing for the production of biodiesel from microalgae

Biofuels produced from algal biomass are the most suitable alternative fuels for the future, as microalgae biomass can accumulate lipids within their cell similar to vegetable oils with a potential to produce 100 times more oil per acrel and than any other plants. The methods used for the extraction of lipid from microalgae are either mechanical or chemical method. The chemical methods of lipid extraction are Soxhlet extraction, supercritical fluid extraction, accelerated solvent extraction and mechanical methods are oil expeller, microwave assisted extraction, ultrasonic assisted extraction. This paper is a review of different methods used for extracting oils or lipids from microalgae biomass for biodiesel production. It is seen that lipid extraction yield from microalgae could be increased by using pretreatment methods such as ultrasonication and microwave-assisted techniques along with solvent extraction.

Sen Zheng

Papers

A simple and rapid harvesting method for microalgae by in situ magnetic separation.

An economic analysis of biomass gasification and power generation in China.

Algal oil extraction from wet biomass of Botryococcus braunii by 1,2-dimethoxyethane

A Demonstration Project for Biomass Gasification and Power Generation in China

Method for extracting botryococcus braunii oil from wet botryococcus braunii fronds