Assessing the mass-culture system and proximate content of Arthrospira maxima local for biogas and biohydrogen productions

Abstract

Arthrospira maxima is a type of local cyanobacteria that has shown success in being grown massively in Indonesia. This research is aimed at looking at the resilience and ability to grow in outdoor conditions using cheap media and following environmental patterns in terms of temperature, sunlight and aeration. In specific purpose is utilization of the obtained biomass for biogas or biohydrogen production. Also, media optimization research from chemical pour grade analyzes into commercial types has been carried out at laboratory scale and field scale. The results show that at the scaling up process from laboratorial to outdoor condition the amount of biomass ratio has decreased by 2–10%, whereas proximate of protein has decreased from 46% to 38%, in contrast starch tends to increase from 10% to 23% and lipid was increase from around 9%–12%. Freshwater and marine water basic media also showing difference in ratio of biomass production and main proximate. The total calory and protein seems higher if A. maxima cultivate using marine water. Cultivation time outdoors turns out to be faster growth when compared to controlled conditions indoors. Biomass analysis results show that the largest content is protein, followed by carbohydrates and lipid. Considering the composition of the proximate, the cyanobacteria biomass tends to be used for biogas conversion rather than alcohol, due to the high protein with less carbohydrate content. Moreover, Arthrospira is cyanobacteria which is capable for producing heterocyst cells that can be excite gas. It was found the cyanobacteria release hydrogen gas around 54 μL/g wet biomasses/day mature culture. However, it should be remembered that this strain is still original or wild type, and can still be developed using both environmental and molecular manipulation approaches. Survival rate from laboratory scale to field scale shows that the microalgae is strong and worthy of consideration for industrial applications. Apart from that, high pH culture conditions are very good for removing contaminants. Also changing the media from pour analyses grade chemicals to commercial chemicals grade only reduces the biomass composition by 2–5% so it is worth considering for commercial applications. Testing various reactors to make biomass as needed with high productivity will be a challenge in the future.