Elephant grass is available continuously and in abundance, but has only been utilized as animal feed, and is sometimes regarded as a nuisance. However, elephant grass contains cellulose, glucose and starch that can be utilized as raw materials for ethanol production. The concentration of ethanol obtained from a study on the production of bioethanol from elephant grass was between 7-11%. To improve the purity of the ethanol, a batch distillation separation process was performed. In the study of bioethanol production from elephant grass, a hydrolysis process was performed at the following fixed condition 30 oC temperature, 7 liter of water, 1 hour of hydrolysis time, while the following variables were changed fermentation period of 4, 5, 6, 7, and 8 days, and starter concentration of 8, 10, and 12%. From the bioethanol production study, the following best condition was obtained: 200 gram of grass, 10% Saccharomyces cerevisiae starter for 6 days. This condition produced 27.71% ethanol, with a 8.09% residual glucose. To obtain a higher purity ethanol product, a subsequent separation using batch distillation was performed, resulting in 90-95% ethanol. Therefore, elephant grass can be used as an alternative raw material for bioethanol production.Keywords: bioethanol, fermentation, hydrolysis, elephant grass Abstrak Ketersediaan rumput gajah dapat diperoleh secara kontinu dan melimpah, seringkali hanya digunakan sebagai makanan ternak, dan terkadang rumput gajah juga dianggap sebagai tanaman pengganggu. Rumput gajah mempunyai kadar selulosa, glukosa, pati yang dapat digunakan sebagai salah satu bahan penghasil etanol. Kadar etanol yang diperoleh dari kajian produksi bioetanol dari rumput gajah antara 7-11%. Untuk meningkatkan kemurnian kadar etanol dilakukan pemisahan menggunakan distilasi batch. Dalam penelitian kajian produksi bioetanol dari rumput gajah dilakukan proses hidrolisis pada kondisi tetap suhu 30 oC, air 7 liter, waktu hidrolisis 1 jam, dan kondisi berubah yaitu berat rumput gajah 50, 100, 150, 200, 250, dan 300 gram, volume larutan HCl 10, 20, 30, 40, 50 mL. Kemudian dilanjutkan proses fermentasi pada kondisi tetap suhu 30 oC, pH 4,5, volume fermentasi 500 mL dan kondisi berubah yaitu waktu fermentasi 4, 5, 6, 7, 8 hari, dan starter 8, 10, dan 12%. Dari penelitian kajian produksi bioetanol dari rumput gajah diperoleh hasil terbaik yaitu: berat rumput gajah 200 gram, starter Saccharomyces cerevisiae 10% selama 6 hari, menghasilkan etanol sebesar 27,71% dan kadar glukosa sisa 8,09%. Untuk memperoleh produk etanol yang lebih murni dilakukan proses pemisahan lanjutan dengan distilasi batch, setelah dilakukan pemisahan lanjut diperoleh kadar etanol 90–95%, sehingga rumput gajah dapat digunakan sebagai bahan baku alternatif pembuatan bioetanol.Kata Kunci: bioetanol, fermentasi, hidrolisis, rumput gajah.
THE EFFECT OF THE TYPE OF ACID CATALYST AND TIME ON % YIELD OF BIOETHANOL FROM ELEPHANT GRASS (Pennistum Purpureum Schumach)
