Strategies for Optimizing Algal Biology for Enhanced Biomass Production

Abstract

One of the most environmentally sustainable ways to produce high-energy density (oils) feed stocks for the production of liquid transportation fuels is from biomass. Photosynthetic carbon capture combined with biomass combustion (point source) and subsequent carbon capture and sequestration has also been proposed in the intergovernmental panel on climate change report as one of the most effective and economical strategies to remediate atmospheric greenhouse gases.To maximize photosynthetic carbon capture efficiency and energy-return-on-investment, we must develop biomass production systems that achieve the greatest yields with the lowest inputs. Numerous studies have demonstrated that microalgae have among the greatest potentials for biomass production.This is in part due to the fact that all alga cells are photoautotrophic, they have active carbon concentrating mechanisms to increase photosynthetic productivity, and all the biomass is harvestable unlike plants. All photosynthetic organisms, however, convert only a fraction of the solar energy they capture into chemical energy (reduced carbon or biomass). To increase aerial carbon capture rates and biomass productivity, it will be necessary to identify the most robust algal strains and increase their biomass production efficiency often by genetic manipulation. We review recent large-scale efforts to identify the best biomass producing strains and metabolic engineering strategies to improve aerial productivity. These strategies include optimization of photosynthetic light-harvesting antenna size to increase energy capture and conversion efficiency and the potential development of advanced molecular breeding techniques. To date, these strategies have resulted in up to twofold increases in biomass productivity.

A Comprehensive Review of the Nutraceutical and Therapeutic Applications of Red Seaweeds (Rhodophyta)

“…Pigments are polar compounds associated with phycobilisomes, which are a regulatory protein complex, with the function of light harvesting and have a pivotal role on photosynthesis by performing light harvesting [20,[83][84][85].…”

Microalgae cultivation and metabolites production: a comprehensive review

“…Figure a shows the photosynthetic apparatus in various algae groups. Understanding the effects of light irradiation intensity, period (duration) and frequency (alternation or continuous) on the photosynthetic efficiency and growth of algae has been an important focus of research . The transfer of a photon to the active center itself is an extremely efficient process, due to the inherent quantum mechanic nature of photons .…”

“…(2009) engineered a smaller PSII antenna size in Chlamydomonas reinhardtii strains with both improved photon conversion efficiency and increased growth rates under high light‐intensity conditions by transformation of an active variant of the light harvesting complex (LHC) translation repressor NAB1 . According to a recent review, some progress has been made in the metabolic engineering strategies of chlorophyll antenna, which resulted in two‐fold increases in biomass productivity . Still, in several cases no significant increase in biomass productivity was observed, possibly also induced by the antenna complex alterations that induce impaired photoprotection mechanisms .…”

Light Acclimation of the Colonial Green Alga Botryococcus braunii Strain Showa

“…Their growth rates are prohibitively low for commercial utilization, despite numerous studies aimed at optimizing growing conditions (Sakamoto et al, 2012;Yoshimura et al, 2013;Kim et al, 2014) and despite the occurrence of natural blooms (Wake and Hillen, 1980). A better understanding of the biology of this alga could identify factors that limit growth and lead to selection of targets for strain improvement (Barry et al, 2015).…”