Potential of Gracilaria sp. as single-or co-digestion feedstock for biogas production

Abstract

High consumption of fossil fuels in Indonesia needs to be reduced by using renewable energy, such as from biomass. In Indonesia, as one of the largest maritime countries, macroalgae (i.e. seaweed) are also considered as potential renewable biomass feedstocks for substituting any land biomass. This study aimed to investigate biodegradability and biogas potential of macroalgae (Gracilaria sp.) as single-or co-digestion feedstock using anaerobic digestion technology. The biochemical methane potential (BMP) test was carried out for 28 days at temperature of 37 °C to investigate the specific methane potential. All samples were in triplicate. Combinations of Gracilaria sp. with various biomass feedstocks (i.e. food waste, tofu dregs) were also tested. The findings indicated a potential valorisation of macroalgae for biogas production either as single or co-digestion feedstock, as well as a potential for electricity generation. However, further optimisation process is required for better and higher degradation process.

Enhancing anaerobic digestion of wild seaweed Gracilaria verrucosa by co-digestion with tofu dregs and washing pre-treatment

“…A high TS concentration resulted in a reduction in hydrolysis rate and an inhibition in methanogenesis due to mass transfers limitations. A previous study also found that an increase in MC values has correlation to an increase in SMP values, and vice versa [48].…”

“…Control positive used in this study was α-cellulose powder C8002 (Sigma Alrdrich, Singapore). Control inoculum was prepared using digestate from a full-scale digester treating cattle manure at Balai Besar Pelatihan Peternakan in Batu City, which operated under mesophilic condition, as previously used in our previous studies [12,48,57,58]. The digestate was sieved using a 1 mm screen for removing larger particles, then it was deggased for 48 hours at 37 o C to eliminate the residual biogas.…”

“…A manual BMP test was used in this study, operated for 28 days at 37 o C, following the method explained in our previous studies [12,48,57,58]. Each sample was prepared in triplicate using a 250-mL serum bottle with working volume of 40 mL.…”

“…Kumar et al [81] reported that co-digestion of waste algal biomass with cattle dung resulted in high methane potential (315 L/kgVSadded) at OLR 5 gVS/L. Various studies have also reported significant improvement in biogas and methane yield following co-digestion of macroalgae with other substrates, such as FW and TD [48]; glycerol and sewage sludge (SS) [54]; FVW [82]; TWAS [83]; cattle manure [84]; waste paper (WP) [85]; as well as. Comparison of other studies on BMP of marine macroalgae in mono-and co-digestion system is shown in Table 2.…”

“…Several studies have reported the potential of native macroalgae which is a non-edible macroalgae in Indonesia for biogas production using the AD process [32,46,47]. Our previous studies have also highlighted that cultivated seaweed (as opposed to wild) G. verrucosa offers good potential to be co-digest with TD, food waste (FW), and wastewater [48]. Furthermore, several studies have also investigated the methane potential from TD as a mono-or co-digestion feedstock in AD process.…”