Abdul Aziz Darwis
Fakultas Teknologi Pertanian, Institut Pertanian Bogor, Kampus Darmaga, Bogor 16680

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The Influence Of Reactant Ratio (Eupcalyptus Lignin – Sodium Bisulfite) And Initial Ph Towards Characteristcs Of Sodium Lignosulfonate Syahbirin, Gustini; Darwis, ABDUL Aziz; Suryani, Ani; Syafii, Wasrin
Journal of Agroindustrial Technology Vol. 19 No. 2 (2009): Jurnal Teknologi Industri Pertanian
Publisher : Department of Agroindustrial Technology, Bogor Agricultural University

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Eucalyptus lignin was isolated from kraft black liquor through by acidification using H2SO4. Sulfonation of eucalyptus lignin produced sodium lignosulfonate (SLS) which can be used as dispersants, and emulsifier. In this research, sulfonation was carried out towards lignin with mass ratio of eucalyptus lignin-NaHSO3 (b/b) of 1:0.4, 1:0.5, and 1:0.6, and initial pH of 5, 6, 7, 8. Studies on the effect of various ratio of eucalyptus lignin versus NaHSO3 (1 based on w/w) and initial pH of 5,6,and 7 for the sulfonation reaction showed an  increasing yield and improved purity of SLS obtained.  However, no significant result was observed on the application of initial pH  7 and 8 toward increasing of SLS yield and purity.  The highest SLS  yield of 83.8% with  purity of 82.9% was obtained under condition of initial pH at 7 and the mass ratio of eupcayptus lignin over NaHSO3 was 1:0.5.  The resulted SLS was light brown, water soluble, with  pH level between 6.3 and 7.24, and released sulfur-like odor.Key words: lignin, kraft black liquor,  sodium lignosulfonate.
Penggandaan Skala Produksi Bioinsektisida Bacillus thuringiensis var. israelensis untuk Membasmi Jentik Nyamuk Aedes aegypti Rahayuningsih, Mulyorini; Syamsu, Khaswar; Darwis, Abdul Aziz; Purnawati, Rini
Jurnal Ilmu Pertanian Indonesia Vol. 12 No. 2 (2007): Jurnal Ilmu Pertanian Indonesia
Publisher : Institut Pertanian Bogor

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The objective of this research is to study the scaling up of bionsecticide production from Bacillus thuringiensisvar. israelensisusing onggok (a cassava by-product) as a carbon source. The insecticide produced was used to eradicate Aedes aegypti larvae. The product was a crystal protein produced during bacterial sporulation. Scaling up from laboratory to pilot plant scale was done using two methods, i.e. constant agitation power per unit volume (Pg/V) and constant oxygen transfer coefficient (kLa). The results showed that yield of product per substrate (Yp/s) of Pg/V based product with the value of 3.52 ± 0.02 spora per gram substrates was higher than Yp/s of  kLa based product with the value of 2.96 spora per gram substrate.  Logarithmic value of viable spore count (log of VSC) was also higher, i.e. 7.23 ± 0.30 for Pg/V based product as compared to 7.17 ± 0.20 for kLa based product. Substrate efficiency was also higher in Pg/V based (92.47%) than kLa based (64.87%). LC50 of Pg/V based product was lower (0.49 μg/ml) meaning that it was more toxic than kLa based product (0.62 μg/ml). Amino acid content of Pg/V based product was also higher than kLa based product. Constant Pg/V method was suggested as a based on the scaling up of bioinsecticide production of B. thuringiensis israe/ensison industrial scale. Keywords: bioinsecticide, Bacillus thuringiensisvar. israelensis, kLa, Pg/V, LC50, viable spore count