ANALISIS PENAMBAHAN BAKTERI Azospirillum sp. TERHADAP KEPADATAN SEL DAN KANDUNGAN LIPID MIKROALGA Chlorella sp. SERTA PENYISIHAN N TOTAL DI LIMBAH CAIR TAHU

Abstract

Abstrak Biomassa mikroalga Chlorella sp. mampu menghasilkan lipid yang dapat dikonversi menjadi biodiesel sebagai energi alternatif bahan bakar fosil disamping perannya dalam pengolahan limbah. Oleh karena itu, teknik budidaya mikroalga tersebut menjadi penting untuk dikembangkan. Salah satunya dengan memanfaatkan bakteri Azospirillum sp. yang bisa meningkatkan pertumbuhan Chlorella sp. dalam pembentukan lipid dan menurunkan kadar pencemar pada limbah cair tahu. Pada penelitian ini dilakukan pengukuran pertumbuhan dan jumlah lipid yang dihasilkan Chlorella sp. serta mengetahui hubungan bakteri Azospirillum sp. dan Chlorella sp. dalam menurunkan kadar penyisihan nitrogen total di limbah cair tahu. Penelitian dilakukan secara batch dengan perlakuan penambahan bakteri dengan 5 level yang berbeda, yaitu 0 (tanpa penambahan bakteri), penambahan bakteri sebanyak 0,25; 0,50; 0,75 dan 1 (%v/v). Proses pengolahan dilakukan selama 13 hari dengan penyinaran cahaya matahari dalam fotobioreaktor. Berdasarkan hasil penelitian, kepadatan tertinggi diperoleh dari perlakuan penambahan 1% bakteri Azospirillum sp. sebesar 9,26 x 10 6 sel/ml. Perlakuan dengan penambahan 1% mampu menghasilkan lipid 24,38% dengan efisiensi penyisihan N total sebesar 66,67%. Abstract Microalgae biomass Chlorella sp. able to produce lipids that can be converted into biodiesel as an alternative energy for fossil fuels in addition to its role in waste treatment. Therefore, it is important to develop this microalgae cultivation technique. One of them is by using the Azospirillum sp. which can increase the growth of Chlorella sp. in the formation of lipids and reducing pollutant levels in tofu liquid waste. In this study, measurements of the growth and amount of lipids produced by Chlorella sp. and knowing the relationship between Azospirillum sp. and Chlorella sp. in reducing the total nitrogen removal rate in tofu liquid waste. The research was conducted in batches with the addition of bacteria with 5 different levels, that is 0 (without the addition of bacteria), the addition of bacteria as much as 0.25; 0.50; 0.75 and 1 (% v/v). The processing is carried out for 13 days by irradiating sunlight in a photobioreactor. Based on the results of the study, the highest density was obtained from the addition of 1% treatment of Azospirillum sp. amounted to 9.26 x 10 6 cells/ml. Treatment with the addition of 1% was able to produce 24.38% lipids with a total N removal efficiency of 66.67%.