Bioethanol Production from Yam (Dioscorea Rotundata) Using Simultaneous Saccharification and Fermentation (SSF)

Yam is a starchy tuber mainly used in food preparation but with high potential applications in other fields such as pharmaceutical and bioplastic production. Colombia is among the top twelve yam producing countries worldwide and ranked first in terms of yield of tons per hectare planted. Yam production has specifically been concentrated in the Caribbean region, which is why this tuber is very little known in the inland regions. In this study, we evaluated Simultaneous Saccharification and Fermentation (SSF) for bioethanol production from yam (Dioscorea rotundata) using Saccharomyces bayanus. Ethanol production technologies involve the fermentation and hydrolysis of consumable raw materials (i.e., sugar cane and corn) which are quite mature around the world. For this reason, the process under analysis combined three phases: 60 min of gelatinization, enzymatic hydrolysis (divided into 40 min of liquefaction with α-amylase and 20 min of saccharification with glucoamylase), and 27 h of fermentation with no enzyme recovery. We used different yam concentrations (10, 12.5, 15, and 18 % w/w) in a wet basis. SSF was monitored along time, and total reducing sugars and ethanol concentration were quantified. The hydrolysis yield, was calculated based on the theoretical starch available in the tuber, was 90 % of starch mass for samples with a yam concentration of 10 and 15 % w/w. Regarding ethanol, the best result (a productivity of 0.19 g/Lh-1) was obtained with the sample with a yam concentration of 10 % w/w. Therefore, yam is a starchy material suitable to produce bioethanol via SSF.

Produksi kultur rendam jamur Aspergillus niger dan Aspergillus oryzae ITBCCL sebagai sumber enzim untuk produksi bioetanol dari singkong

Bio ethanol is a very attractive fuel source for communities or even countries that wish to be self-sustainable and not reliant on foreign resources. A variety of feedstock materials may be used to produce ethanol, such as glucose or starchy material (cassava, corn, etc.), by preparing it with a hydrolysis pre-treatment to form glucose. The enzymatic hydrolysis of starch requires at least two different enzymes such as α-amylase for liquefaction process and maltase for saccharification process. The main objective of this research is to produce sub-merged culture enzyme from Aspergillus sp that contained α-amylase and maltase enzymes in sufficient quantity to convert starch which is contained in cassava powder to form glucose. Aspergillus niger CCL 74 ITB and Aspergillus oryzae CCL ITB were cultivated in sub-merged culture. The main raw material of the medium had been varied between vinase from molasse and cake from peanut. Sub-merged culture from Aspergillus niger CCL74 ITB in the vinase medium gave higher a-amylase and maltase activities, compare to sub­ merged culture from A. oryzae CCL ITB. Using vinase from molasse gave higher enzymes yield than using medium from peanut cake.Keywords: α-amylase and Maltase, Sub-merged culture of Aspergillus niger. Aspergillus oryzae AbstrakBahan bakar hayati seperti bioetanol merupakan bahan bakar ramah lingkungan yang potensial dalam mengurangi impor BBM Indonesia. Rute utama pembuatan bioetanol adalah viafermentasi bahan berkarbohidrat. Bahan berkarbohidrat yang potensial dikembangkan di Indonesia dalam produksi bioetanol adalah singkong. Proses konversi pati dalam singkong menjadi etanol biasanya dilakukan melalui proses enzimatik yaitu proses likuefaksi oleh enzim α-amilase, proses sakarifikasi oleh enzim maltase dan fermentasi. Tujuan penelitian ini adalah mendapatkan kultur jamur Aspergillus sp. yang menghasilkan enzim α-amilase dan maltase dalam kuantitas memadai yang akan digunakan sebagai sumber enzim penghidrolisis pati dalam singkong. Jenis jamur yang digunakan Aspergillus niger CCL 74 ITB dan Aspergillus oryzae CCL ITB. Bahan baku utama medium divariasikan antara vinase dan bungkil kacang tanah. Kultur Aspergillus niger CCL74 ITB memberikan aktivitas a-amilase dan maltase yang lebih tinggi dibandingkan dengan kultur Aspergillus oryzae CCL ITB. Penggunaan vinase memberikan hasil yang lebih baik dibandingkan dengan medium bungkil kacang tanah dalam produksi kedua enzim.Kata Kunci: Enzim α-amilase, Glukoamilase, Aspergillus niger. Aspergillus oryzae

Performance of Mixed Cellulase-Amylase Immobilized on PSF Membrane Support via Cross-Linked with Glutaraldehyde in Enzymatic Hydrolysis

A Cellulase and amylase are important enzymes for hydrolysis of cellulose and starchy material into the glucose. The performance of the mixed cellulose-amylase immobilized on polysulfone membrane (PSF) by cross-linked with glutaraldehyde was investigated. PSF membrane consists of 1-methyl-2-pyrolidone (NMP) as a solvent and using polyvinylpyrolidone (PVP) as an additive was developed. The study highlighted in the surface structure of PSF membrane, stability of the immobilized enzyme and reusability of the immobilized enzyme. Morphology studied using FESEM analysis indicated a good distribution of the pores was formed on the surface of the PSF membrane. The immobilization process shown no effect on the membrane structure and it was stable to be used as a support in immobilization process. The optimum operating condition for enzymatic hydrolysis of mixed cellulase-amylase on PSF membrane was 50°C and pH 5. The maximum glucose produced at the optimum condition was 4.843g/ml. The study also indicated that immobilized mixed cellulase-amylase achieved a maximum rate of reaction at first recycle of reusable before the rate of reaction decreased rapidly after 5 reusable hydrolysis cycles.

POTENTIAL USE OF AN EXTRACELLULAR ENZYME OF a-AMYLASE FROM INDIGENOUS INDONESIAN MESOPHILIC BACTERIA

Amylase enzyme has a great significance for industrial usages in Indonesia. However, this enzyme is still imported. The use of bacteria in biotechnological process of industrial products such as enzyme production has stimulated the exploration of extracellular amylase producing bacteria. This study aimed to identify and analyze the potential use of amylolytic bacterial enzymes for hydrolyzing cassava starch. Two bacterial isolates, i.e. MII-10 and DKW-8 originated from Indonesia soil were identified based on their morphological, physiological and biochemical properties according to the standard protocol. The isolates were then cultivated on fermentation medium and their growth pattern and enzymatic assays were observed. The acetone-precipitated crude enzyme harvested based on predetermined cultivation time was used for enzymatic hydrolysis product characterization on cassava starch using thin layer chromatography (TLC). The results showed that the mesophilic<br />bacteria isolates (MII-10 and DKW-8) were belonged to Bacillus licheniformis. The maximum bacterial cell growth and enzyme activity were reached at 48 hours after incubation. The MII-10 isolate was found more stable than DKW-8 in producing amylase enzyme. Amylase produced by the MII-10 and DKW- 8 isolates was identified to be an endo-a-amylase as confirmed by oligosaccharides and dextrin of the random hydrolysis<br />products. Relatively high dextrose equivalence (DE) value of a-amylase of MII-10 (DE of 9.96) suggests that the enzyme is prospective for saccharification of starchy material in glucose syrup industry.<br /><br />

POTENTIAL USE OF AN EXTRACELLULAR ENZYME OF a-AMYLASE FROM INDIGENOUS INDONESIAN MESOPHILIC BACTERIA

Amylase enzyme has a great significance for industrial usages in Indonesia. However, this enzyme is still imported. The use of bacteria in biotechnological process of industrial products such as enzyme production has stimulated the exploration of extracellular amylase producing bacteria. This study aimed to identify and analyze the potential use of amylolytic bacterial enzymes for hydrolyzing cassava starch. Two bacterial isolates, i.e. MII-10 and DKW-8 originated from Indonesia soil were identified based on their morphological, physiological and biochemical properties according to the standard protocol. The isolates were then cultivated on fermentation medium and their growth pattern and enzymatic assays were observed. The acetone-precipitated crude enzyme harvested based on predetermined cultivation time was used for enzymatic hydrolysis product characterization on cassava starch using thin layer chromatography (TLC). The results showed that the mesophilic<br />bacteria isolates (MII-10 and DKW-8) were belonged to Bacillus licheniformis. The maximum bacterial cell growth and enzyme activity were reached at 48 hours after incubation. The MII-10 isolate was found more stable than DKW-8 in producing amylase enzyme. Amylase produced by the MII-10 and DKW- 8 isolates was identified to be an endo-a-amylase as confirmed by oligosaccharides and dextrin of the random hydrolysis<br />products. Relatively high dextrose equivalence (DE) value of a-amylase of MII-10 (DE of 9.96) suggests that the enzyme is prospective for saccharification of starchy material in glucose syrup industry.<br /><br />