Fuel options from microalgae with representative chemical compositions

Abstract

high-lipid producers, t h r e e high-carbohydrate producers, t h r e e high-protein producers, and one high-glycerol producer.Based on t h e chemical compositions r e p o r t e d f o r t h e various s p e c i e s , an e s t imate i s f i r s t made of t h e g r o s s energy content a v a i l a b l e from a u n i t mass of each s p e c i e s .Then, options a r e considered t h a t convert each f r a c t i o n i n t o t h e d e s i r e d products.For example, t h e e n t i r e mass might be converted t o methane, t h e carbohydrate fermented t o e t h a n o l , t h e l i p i d converted t o ester f u e l , o r any combintaion of these. ConclusionsAmong t h e high-lipid producing s p e c i e s , Botryococcus b r a u n i i i s unique i n t h a t i t can produce hydrocarbons a t 40% o r higher of i t s t o t a l l i p i d s .Most of t h e s e hydrocarbons a r e benzene-extractable, aromatic-type compounds, which might be d i r e c t l y usable a s l i q u i d f u e l . o f f e r g r e a t p o t e n t i a l a s sources f o r t h e production of methane v i a anaerobic d i g e s t i o n .Due t o t h e i n h e r e n t l y lower energy requirements and higher conversions f o r t h i s process, energy u t i li z a t i o n e f f i c i e n c i e s range from about 68% ( f o r high-protein producers) t o 7 5 % ( f o r high-lipid producers).The high-protein producing s p e c i e s , a s w e l l a s another s t r a i n of D. s a l i n a t h a t produces about 28% g l y c e r o l , might have a n economic advantage due t o t h e i r coproduction of h i g h e r valued products. D e t a i l e d examinations of a l g a l p r o d u c t i v i t y d a t a , a s w e l l a s economic s t u d i e s , a r e not required t o f u r t h e r q u a n t i f y t h e p o t e n t i a l of t h e s e organisms a s renewable f u e l producers.

Microalgae as second generation biofuel. A review

“…The starch content of algae is reported to reach much higher values which are comparable to corn, wheat and other conventional ethanol feed stocks (Feinberg 1984;S and T 2003). Microalgae have high potentiality for bioethanol production; which may be because of their high rate of productivity, high fermentable carbohydrates content of the biomass and lack of lignin in comparison to the terrestrial feedstocks (Table 3; Moore 2009).…”

An overview of the potential environmental impacts of large-scale microalgae cultivation

“…Microalgae have cultivation benefits compared with other bioenergy crops because of their high growth rates and the option to use marginal land for cultivation. A report produced for the US DOE in 1984 looked at the chemical composition of eight strains of microalgae and calculated fuel production options based on their carbohydrate/protein/lipid content, demonstrating a combination of fuels that can be feasibly produced from an algal crop [23]. It is possible to produce biodiesel, bioethanol, biogas, bio-oil and even bio-hydrogen, as shown in Table 2 [24].…”

“…The energy content of biofuels from microalgae is comparable to those from other bio-crops and also fossil fuels. A summary of the energy contents is given in Table 2, based on an assumption of the following energy values for each characteristic: 38.93 MJ/kg for lipids, 23.86 MJ/kg for proteins and 15.92 MJ/kg for carbohydrates [23] In order to identify the research needs for the successful production of microalgal biofuels, the US DOE developed a roadmap for algae biofuels. Within it, they described the need to understand the scale of benefits microalgae could bring if it were to be included into a fuel mix.…”

“…The use of microalgae could allow the recovery of low levels of P from sources in which other methods may be less economically viable. Bioethanol from algae 23.4 Fermentation [23] Biogas from algae 37.2 Anaerobic digestion, hydrothermal treatment [23] Bio-oil from algae 33-39 Hydrothermal liquefaction [27] Hydrogen from algae 144 Biological production, hydrothermal processing [28] Biodiesel from soya 37.2 Transesterification [29] Gasoline 45 Distillation of crude oil [30] Diesel 48 Distillation of crude oil [30] a The final energy density of the refined fuels is dependent on the composition of lipids and the biochemical composition of the starting microalgae…”

Sintesis Biodiesel dari Minyak Mikroalga Nannochloropsis Sp. Melalui Transesterifikasi Menggunakan Katalis Basa

“…Nannochloropsis sp. merupakan salah satu jenis dari mikroalga yang menghasilkan produk utama lipid [3]. Pemanfaatan mikroalga jenis ini di Indonesia hanya sebatas sebagai pakan ternak ikan dan udang.…”