Judul: Process engineering of cassava pulp hydrolysis using microwave heating for ethanol production
Abstrak: Cassava pulp is a potential source of carbohydrates. In this work, characteristics of the cassava pulp were analyzed and validity of microwave irradiation for hydrolysis of carbohydrates, especially starch present in the cassava pulp, was estimated as a non-enzymatic saccharification technique. The hydrolysis was performed in water and acid medium. In addition, the role of activated carbon in the microwave-assisted hydrolysis was also evaluated. An optimization of the hydrolysis was conducted using Central Composite Design (CCD) and was analyzed using Response Surface Methodology (RSM). Fermentation of cassava pulp hydrolysates produced from microwave-assisted acid hydrolysis was performed to those added with activated carbon (25% w/w) and those without activated carbon by Saccharomyces cerevisiae. There were two types of activated carbon, which have different adsorption properties, used in this experiment. Results of the cassava pulp characterization shows that the starch granules in the cassava pulp were trapped in biomass matrices, so that the starch was harder to hydrolyze than the free starch, such as that in tapioca flour. Microwave-assisted hydrolysis of cassava pulp can be completed in less than 15 minutes in water medium, and less than 10 minutes in acid medium. The addition of activated carbon improved hydrolysis of cassava pulp starch in water medium with suppression of formation of the secondary decomposed materials. The highest glucose yield obtained from cassava pulp was 46% of dry matter or 52% of theoretical, which was about 60% higher than the one without the addition of activated carbon. On the contrary, the addition of activated carbon decreased the glucose yield when the hydrolysis was performed in acid medium (0.5% H2SO4). The glucose yield could reach 80.8% of dry matter or 91.5% of theoretical yield when no activated carbon was added in the acid medium. The estimated optimum condition for cassava pulp hydrolysis under microwave irradiation was using 0.88% sulfuric acid with 9 minutes of heating time, which resulted in 85% of theoretical glucose yield and 140 g/L glucose concentration. At the end of the fermentation the ethanol yield and concentration obtained in the samples treated with activated carbon (0.41-0.43 g ethanol / g glucose consumed; 34-35 g/L) were lower than that not treated with activated carbon or those treated with activated carbon which was added after hydrolysis (0.48 g ethanol / glucose consumed; 38- 39 g/L). However, the fermentation was completed very much faster in the hydrolysates treated with the activated carbon which has a high adsorption capacity than in that not treated with activated carbon or those treated with activated carbon of low adsorption capacity. Therefore, ethanol productivities (0.44-0.55 g/L/h) of the former were higher than the latter (0.28-0.34 g/L/h).
Keyword: 

Judul: Detoxification of Cassava’s Acid Hydrolyzate by Activated Carbon Method for Bioethanol Production
Abstrak: Cassava is one of natural resources for carbohydrate that also available for bioethanol production. Starch and fibers hydrolysis maybe conducted on acid condition. The restriction in acid hydrolysis is 5-hydroxymethyl furfural (HMF) and furfural formation, which inhibit yeast fermentation. This study applied two stages of detoxification, which are overliming and activated carbon adsorption methods for lowering HMF and furfural concentrations. In order to obtain tolerable amount in sugar solution, detoxification by activated carbon adsorption was done by concentration of 1%, 2.5%, 5% and 10% and duration of contact are 30 45 and 60 minutes. The results showed that overliming method decreased HMF and furfural concentrations 34.38% and 60.81%, respectively. Overliming followed by 5% activated carbon adsorption for 30 minutes produced the best sugar solution which has a lower HMF and furfural concentrations by 72.03% and 89.11%, respectively. Adsorption constants of HMF and furfural by 5% activated carbon were 0.044 g/min and 3,7 x 10-5 g/min, respectively. The concentration of ethanol produced was 5.00% (b/v) or 63.22% higher than obtained from detoxification by neutralization (NH4OH) which produced ethanol only 3.06%.
Keyword: 

Judul: Keragaman Spesies Ular Temuan Masyarakat di Area Permukiman Wilayah Jabodetabek.
Abstrak: Pembangunan dan kehilangan habitat di Jakarta, Bogor, Depok, Tangerang, Bekasi (Jabodetabek) berdampak pada ular yang harus beradaptasi di ekosistem urban dan meningkatkan perjumpaan dengan manusia. Ular di sekitar permukiman dapat menimbulkan konflik antara manusia dengan ular. Komunitas reptil, Pest Control, dan Pemadam Kebakaran sering kali mendapat panggilan untuk relokasi ular. Penelitian ini bertujuan untuk mengetahui keragaman jenis ular yang sering dijumpai warga di permukiman Jabodetabek, serta mendokumentasikan upaya yang telah dilakukan organisasi dalam mitigasi konflik melalui relokasi ular di permukiman. Data dihimpun dengan cara studi data sekunder dan wawancara. Terdapat 37 jenis ular yang ditemukan warga atau 75% dari seluruh jenis ular yang ada di Jabodetabek. Naja sputatrix adalah jenis yang paling banyak ditemukan. Jakarta adalah wilayah terbanyak laporan perjumpaan ular. Konflik manusia dengan ular dimitigasi dengan relokasi ular, edukasi, dan translokasi meskipun harus ada evalusi lebih lanjut mengenai dampak translokasi.
Keyword: Jabodetabek, Keragaman, Mitigasi konflik, Naja sputatrix, Ular