Abstract
The potential of microalgae biomass production for low-cost commodities—biofuels and animal feeds—using sunlight and CO2 is reviewed. Microalgae are currently cultivated in relatively small-scale systems, mainly for high value human nutritional products. For commodities, production costs must be decreased by an order of magnitude, and high productivity algal strains must be developed that can be stably cultivated in large open ponds and harvested by low-cost processes. For animal feeds, the algal biomass must be high in digestible protein and long-chain omega-3 fatty acids that can substitute for fish meal and fish oils. Biofuels will require a high content of vegetable oils (preferably triglycerides), hydrocarbons or fermentable carbohydrates. Many different cultivation systems, algal species, harvesting methods, and biomass processing technologies are being developed worldwide. However, only raceway-type open pond systems are suitable for the production of low-cost commodities.
Highlights
This review addresses the autotrophic, that is, using sunlight and CO2, production of microalgae biomass for low-value commodities, biofuels and animal feeds, products with plant-gate value of $1000/t or less
There is no agreement yet about even such basic issues as the best production technology for microalgae (PBRs or hectare raceways ponds (HRPs)), the currently or potentially achievable productivities, or the climatic limitations to such processes. This review addresses these issues and the research and development (R&D) needed to achieve the goal of microalgae commodities production
Waters; (b) Dunaliella salina grows at high salinity (>100 g/L, >3× seawater), produces beta-carotene; (c) Haematococcus pluvialis, red color due to astaxanthin, a carotenoid used in aquaculture feeds and nutritional products; (d) Chlorella vulgaris, first microalgae produced commercially for human foods; (e) Amphora sp., as with most diatoms, requires large amounts of silicate, increasing production costs; (f) Nannochloropsis sp., grown in seawater, is a popular species for biofuel/feed production; (g) Micractinium sp., grown in wastewater, can aggregate into large flocs (“bioflocculation”); (h) Botryococcus braunii, a unique hydrocarbon producing species; and (i) Anabaena cylindrica, a nitrogen-fixing cyanobacterium with potential for fertilizer production
Summary
This review addresses the autotrophic, that is, using sunlight and CO2, production of microalgae biomass for low-value commodities, biofuels and animal feeds, products with plant-gate value of $1000/t (metric ton of ash-free dry weight of algal biomass) or less. There is no agreement yet about even such basic issues as the best production technology for microalgae (PBRs or HRPs), the currently or potentially achievable productivities (tons of biomass or liters of biofuels per hectare per year), or the climatic limitations to such processes. This review addresses these issues and the R&D needed to achieve the goal of microalgae commodities production. It is based on the author’s prior work in this field and his familiarity with the current commercial production of microalgae nutritional products. The starting point is an overview of the practical, that is, commercial, experience in microalgae production, as it has developed over the past fifty years
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call