Optimasi Pretreatment melalui Metode Hydrothermal Pressure dan Pelarut Alkali pada Produksi Bioetanol dari Lemna minor

Abstract

Produk bioetanol dengan bahan dasar biomassa lignoselulosa perlahan banyak dikembangkan sebagai sumber energi alternatif. Tantangan utama dalam produksi lignoselulosa etanol berada pada tahap pretreatment. Pretreatment merupakan tahap yang memegang peranan penting dalam mendegradasi lignoselulosa menjadi selulosa. Pada penelitian ini digunakan Lemna minor yang merupakan gulma perairan dengan kombinasi dua tahap pretreatmen untuk melihat efektivitas degradasi lignoselulosa dalam sampel. Tahap pertama dengan metode hydrothermal pressure pada suhu pemanasan uap 121 °C dan tekanan 15-20 psi dengan variasi waktu proses selama 5, 15, 30, 45, dan 60 menit. Tahap kedua pretreatment dengan metode kimiawi menggunakan NaOH dengan variasi konsentrasi 0,5; 1; 1,5; 2; dan 2,5 M. Hasil penelitian menunjukkan 60 menit merupakan waktu optimum dari metode hydrothermal pressure pada sampel L. minor dengan kadar lignin 11,32%, kadar selulosa 17,39%, kadar hemiselulosa 16,73% dan kadar gula total 0,82%. Untuk tahapan pretreatment dengan pelarut alkali (NaOH) kandungan kadar lignin L. minor setelah pretreatment dengan NaOH 2,0 M sebesar 5,36%, kadar.  Kandungan kadar selulosa, hemiselulosa dan gula total optimum diperoleh pada konsentrasi 2,5 M dengan nilai kadar 31,03%; 5,57% dan 1,74%. Efektivitas penurunan kadar lignin pada pretreatment hydrothermal pressure sebesar 37,04% sedangkan pretreatment dengan NaOH sebesar 70,18%. Kombinasi proses pretreatment memberikan hasil yang cukup baik terhadap proses degradasi lignin yang terkandung dalam sampel Lemna minor sehingga sangat efektif digunakan dalam proses pembuatan bioetanol dengan bahan dasar biomassa.  

Optimization Pretreatment through Hidrothermal Preassure and Alkaline Solvent Methods in Bioethanol Production from Lemna minor. Bioethanol products with lignocellulosic biomass feedstock have been developed as an alternative energy source. The main challenge in the production of lignocellulosic ethanol is on the pretreatment stage. Pretreatment is a stage that plays an important role in degrading lignocellulose into cellulose. In this study, we used a Lemna minor which is a water weed with a combination of two stages of pretreatmentt to see the effectiveness of lignocellulosic degradation in the sample. The first stage is hydrothermal pressure method of steam heating temperature 121 °C and pressure 15-20 psi with variation of processing time for 5, 15, 30, 45, and 60 minutes. The second stage of pretreatment with chemical methods using NaOH with a concentration variation of 0.5; 1; 1.5; 2 and 2.5 M. The results showed that 60 minutes was the optimum time of the hydrothermal pressure method in the L. minor sample with the lignin content of 11.32%, the cellulose 17.39%, the hemicellulose 16.73% and the total sugar 0.82%. For the pretreatment stage with alkaline solvent (NaOH) the content of L. minor lignin after pretreatment with 2.0 M NaOH was 5.36%. The content of cellulose, hemicellulose and total sugars was obtained at a concentration of 2.5 M with a grade value of 31.03%, 5.57%, and 1.74%. The effectiveness of lignin decrease in pretreatment hydrothermal pressure was 37.04% while pretreatmentt with NaOH was 70.18%. The combination of pretreatment process gives a good result to the lignin degradation process contained in the L. minor sample in order that it is very effective in the process of making bioethanol with biomass feedstock.