The Colonial Microalgae Botryococcus braunii as Biorefinery

Abstract

The growing shortage of fossil fuels caused an increase in the demand for alternative and renewable fuels. Biofuels, like bioethanol and biodiesel, have received more attention as a sustainable replacement of fossil fuels. However, these have a poor oxidative stability, little energy content by volume, and many oxygenated compounds, which may cause corrosion and damage to the engines. Therefore, they are used as a mixture with standard fuels. Some species of microalgae are candidates to produce oils as triglycerides (TGA) to produce biodiesel by transesterification; however, the problem will remain. The colonial microalgae Botryococcus braunii produces and accumulates a high amount of long-chain nonoxygenated hydrocarbons, similar to those obtained from the fractionated distillation of crude petroleum. This is one of the few organisms reported to have a direct contribution in the formation of the oil reserves currently in use. Additionally, B. braunii produces pigments and long-chain carbohydrates that have interesting properties for various industries. There are still problems to be solved in order to consider it as economically viable and profitable, but important progress is being made. Therefore, this microalga is very attractive for the synthesis of hydrocarbons and other value-added compounds, making it an interesting biorefinery organism.

Large-scale screening of natural genetic resource in the hydrocarbon-producing microalga Botrycoccus braunii identified novel fast-growing strains

“…Wastewater treatment by B. braunii removes nutrients 55 and heavy metals 56 and may also be effective for pharmaceutical products remediation as recently reported in other microalgae 57 . Substantial amounts of high-value chemicals aside from hydrocarbons are also identified in B. braunii 24 , 58 . These potential applications can be combined with hydrocarbon production in a biorefinery from B. braunii .…”

“…To overcome the slow growth of B. braunii , we searched for novel fast-growing strains from natural genetic resources. The Showa strain, known as a fast-growing strain of B. braunii , holds the fastest growth record with a doubling time of 1.4 days 22 and the highest record of hydrocarbon productivity (340 mg L −1 d −1 ) to date 23 , 24 . This strain is a wild strain isolated from the pond of a greenhouse in California in the 1980s and was not selected by screening or artificially modified by mutagenesis 25 .…”

Strategies for the production of biochemicals in bioenergy crops

“…Genetic engineering in Brachypodium resulted in higher titers of botryococcene (> 1 mg/g FW) and healthier plants were obtained using the cytosolictargeting strategy instead of a plastid-targeting approach [296]. Although these plant engineering efforts are promising, improving growth rates and certain physiological characteristics of B. braunii strains represent concrete research avenues towards converting this natural host into a biorefinery organism for industrial production of long-chain non-oxygenated hydrocarbons [297].…”

Efecto de nutrientes en el rendimiento de biomasa de Botrycoccus braunii para la obtención de biodiesel

“…2.1 Materia prima Se utilizaron micro algas Botryococcus braunii aislada de las lagunas de Alto Perú en la zona de Cajamarca -Perú, en la figura 1 se muestra la zona de muestreo A, B y C a 3933 m.s.n.m., en la Zona 17M con coordenada este de 763334.99 m E y coordenada norte de 9236298.22 m S. Para el aislamiento de la microalga se empleó la técnica de dilución y enjuague con medio CHU 13 mostrado en la Tabla I [13]. Las características morfológicas observadas en la cepa obtenida de las lagunas de Alto Perú coinciden con lo reportado por Lozoya [14], una micrografía se muestra en la Figura 2. 2.2 Toma de muestra de medio de biorreactor Se usaron frascos de plástico resistente, en los que la biomasa de microalgas no se adhiera a las paredes del recipiente, se usó una intensidad lumínica de 5000 luxes, temperatura entre 20 ±2 °C y fotoperiodo 12:12 con 5% de inoculo.…”