Optimum Fermentation Process for Red Macroalgae Gelidium latifolium and Gracillaria verrucosa

Abstract

Abstract. Red macroalgae have the potential to be processed into bioethanol due to their high carbohydrate and low lignin content. Gelidium latifolium and Gracilaria verrucosa are red macroalgae commonly found in Indonesian seas. Sometimes an over-supply of red macroalgae is rejected by the food industry, which opens up opportunities for others uses, e.g. for producing bioethanol. The objectives of this research were to analyze the influence of sulfuric acid concentration on hydrolysis of G. latifolium and G. verrucosa and to calculate the optimum fermentation process to produce bioethanol. G. latifolium and G. verrucosa were hydrolyzed using H 2 SO 4 at concentrations of 1%, 2%, 3%, and 4%, at a temperature of 121 °C and a pressure of 1.5 bar for 45 minutes. The process of fermentation was done using Saccharomyces cerevisiae in anaerobic conditions for 4, 5, 6 and 7 days. The results show that the optimum H 2 SO 4 concentrations to hydrolyze G. latifolium and G. verrucosa were 1% and 2% respectively. The number of S. cerevisiae cells in hydrolysate G. latifolium and G. verrucosa increased in the third adaptation. S. cerevisiae can convert sugar from G. latifolium and G. verrucosa into bioethanol through fermentation. The highest bioethanol yields were achieved on days five and six. Therefore, red macroalgae can be seen as a potential raw material for bioethanol production.

Commodity chemical production from third‐generation biomass: a techno‐economic assessment of lactic acid production

“…Physical pretreatment involves washing the biomass with fresh water to remove the high content of salt, sand, and other traces, which can affect the efficiency of microorganisms during fermentation 44 . As mentioned above, the feedstock has a high water content, making it suitable for fermentation processes 41 . Thus, ideally, a drying step would not be required, implying the possibility of skipping this stage in the physical pretreatment (as shown in Fig.…”

Seaweed Exhibits Therapeutic Properties against Chronic Diseases: An Overview

“…Moreover, proximate analysis on red seaweed found an average value for ash content of 22.9 ± 10.99 g/100 g, which is much higher than that in terrestrial plants [61]. These results were confirmed in red seaweed Gelidium elegans, containing 24.1% ash dw [62], and the total ash of Gracilaria verrucosa reached as high as 48.68% dw [50].…”

“…Among seaweeds, red seaweed contains the highest protein content, which ranges from 0.67% to 45.0% dw, followed by green seaweed (3.42-29.80% dw) and brown seaweed (5.02-19.66% dw) [49]. Specifically, the protein content of red seaweed varies, with values of 9.32% dw for Gelidium latifolium, 15.58% dw for Gracilaria verrucosa [50], and 26.69% dw for Plocamium telfairiae [51]. Green seaweeds such as Caulerpa lentillifera, Ulva rigida, and Ulva pertusa contain protein contents of 7%, 9.3%, and 21.5% dw, respectively [4,46].…”

“…The ash content of seaweed is quite high compared to common land plants, ranging from 8.0% to 48.68% dw [15,50]. However, this amount depends on several factors.…”