Maria Dyah Nur Meinita

Detoxification of acidic catalyzed hydrolysate of Kappaphycus alvarezii (cottonii).

Red seaweed, Kappaphycus alvarezii, holds great promise for use in biofuel production due to its high carbohydrate content. In this study, we investigated the effect of fermentation inhibitors to the K. alvarezii hydrolysate on cell growth and ethanol fermentation. In addition, detoxification of fermentation inhibitors was performed to decrease the fermentation inhibitory effect. 5-Hydroxymethylfurfural and levulinic acid, which are liberated from acidic hydrolysis, was also observed in the hydrolysate of K. alvarezii. These compounds inhibited ethanol fermentation. In order to remove these inhibitors, activated charcoal and calcium hydroxide were introduced. The efficiency of activated charcoals was examined and over-liming was used to remove the inhibitors. Activated charcoal was found to be more effective than calcium hydroxide to remove the inhibitors. Detoxification by activated charcoal strongly improved the fermentability of dilute acid hydrolysate in the production of bioethanol from K. alvarezii with Saccharomyces cerevisiae. The optimal detoxifying conditions were found to be below an activated charcoal concentration of 5%.

Complete sequences of the mitochondrial DNA of the Grateloupia filicina (Rhodophyta)

Abstract In this study, we sequenced and analyzed the complete mitogenome of Grateloupia filicina (Lamouroux) C. Agardh. The complete G. filicina mitogenome was 29,274-bp long, containing 51 genes, including 24 protein-coding genes, 1 intron, 2 rRNA genes, 24 tRNA genes, and 1 unidentified open reading frame. Twenty-one of the 24 (87.5%) protein-coding genes ended with the stop codon TAA, whereas 3 (12.5%) ended with TAG. All the protein-coding genes in G. filicina used the start codon ATG. Phylogenetic analysis revealed that G. filicina clustered with G. taiwanensis. The complete mitochondrial genome sequence provided here would be useful for understanding the evolution of Grateloupia further.

Neurotrophic Activity of the Carrageenophyte Kappaphycus alvarezii Cultivated at Different Depths and for Different Growth Periods in Various Areas of Indonesia

The carrageenophyte Kappaphycus alvarezii (Rhodophyta) has neurotrophic activity in primary hippocampal neurons. This seaweed is abundant and easily cultivated in tropical coastal areas. To determine the best growth conditions for neurotrophic activity, thalli were grown at different depths and for different periods in various areas of Indonesia. Neurotrophic activity was measured based on the number of primary neurites, the total length of the primary neurites, and the length of the longest neurite. K. alvarezii had higher neurotrophic activity than carrageenophytes K. striatum and Eucheuma denticulatum cultured under the same conditions. K. alvarezii grown at the surface for 45 days had higher (1.4- to 1.8-fold) neurotrophic activity than thalli grown at depth (2 m) or harvested sooner (15 days) (P < 0.05). Relatively high activities were detected in thalli cultured at Ternate and Garut, Indonesia. Therefore, from a commercial perspective, the culture conditions at the surface for 45 days were optimal for the production of both neurotrophic compounds and carrageenan. K. alvarezii produced neurotrophic compounds under various environmental conditions, although some conditions were optimal.

The complete mitochondrial genome of the economic red alga, Gracilaria chilensis

Abstract Gracilaria chilensis is an economically important marine alga. In this study, we obtained complete mitogenome of G. chilensis by high-throughput sequencing, which was mapped as a circular molecule of 26,897 bp with 27.56% GC content and was identified 53 genes, including 25 protein-coding genes, 2 rRNA genes, 26 tRNA genes, and 1 group II intron inserted into the trnI gene. In addition, a 162-bp stable stem loop was found in intergenic regions, which was most likely associated with DNA transcription and replication. The Bayesian phylogenetic tree of Gracilariaceae revealed that G. chilensis and G. salicornia and G. changii shared a closer relationship than G. vermiculophylla in the genus Gracilaria.