After many years of research, some feel that we have elucidated the functioning of the photosynthetic machinery and limitations therein, and what sets the upper limit for algal growth. However, the unparalleled fast growth, extremely high photosynthetic rates and resistance to photodamage, salinity and desiccation displayed by C. ohadii, recently isolated from a biological desert sand crust (BSC), one of the harshest environments to support life, suggest this may not be the case. When grown under optimal laboratory or controlled outdoor facility conditions it exhibits the fastest growth rates ever reported for an alga. The cultures perform among the highest photosynthetic rates ever reported and reach very high cell densities (1.3*109 cells/mL).
Unlike other photosynthetic organisms, C. ohadii productivity is unaffected by irradiances as high as twice full sun light; and the level of protein D1, encoded by a single gene in the C. ohadii genome (56 MB), is hardly affected. Following exposure to high irradiance, C. ohadii cells undergo major structural (i.e. pyrenoid development and increased thylakoid abundance) and compositional changes (i.e. a 2-3 fold increase of the lipid and carbohydrate contents).
In view of the unparalleled growth and photosynthetic performance, C. ohadii may be used in future research to clarify the processes that rate-limit growth and productivity of photosynthetic organisms; In an era where novel approaches to raise biomass production for food or energy supply are being explored C. ohadii may be used either directly in algal farms or as a gene source for the development of crop plants that can maintain high yields in environments not suited to current cultivars.
