The quality of Indonesiam coffee andcocoa products has been declined due to the contamination of fungi producing ochratoxin, a serious human mycotoxin. Therefore, development of fast, accurate and simple method for early detection of ochratoxin contamination is required. As a part of research attempted to develop early detection technique of ochratoxin in severall commodities, especially agricultural products, the objective of this study was to produce immunochemical reagent for ochratoxin detectionusing immunoglobulin Y (IgY) based on immunochromatographic method. Results showed that OTA-OVA could be synthesized using active ester method with addition of N-hydroxysucciimide and dicyclocarboimide. The intermediate compound produced showed C=O stretching vibrational band at 1600 cm-1 and CO stretching vibrational band at 1300-1000 cm-1. Antibody-gold nanoparticle conjugate was optimally produced at pH 9 and with antibody dilution of 1:7.5 (v/v). There was 50 nm absorbtion shift in visible absorbtion after the antibody was conjugated with gold nanoparticle. Even though the test strip did not show clear visualization, the cut off of ochratoxin concentrationis obviously determined at 10 ppb. This results suggest thatthe technique could be used to detect ochratoxin contamination.
SummaryDownstream industry of palm oil producing specialty oil with higher economic value compared to that of CPO in Indonesia is less developed due to technical obstacle and the availability of supporting materials. Specific lipase 1,3-glyceride for example which is used for oleochemical processing of healthy oil production is still imported with relatively high price. Healthy oil can be made from CPO bioconversion using the enzyme that produces oil rich in diacylglycerol (DAG). Although research on the production and the use of lipase has been well studied, production of specific lipase from microbes of local source is still very limited. This article reports one part of the series of the research activities on bioprocess and genetic engineering approaches to produce specific lipase for bioconversion of CPO i.e optimization of 1,3-glyceride-spesific lipase production from fungi selected from local sources. Based on the fluorescence zone on the screening media, of the twenty isolates collection, it was found that P6 isolate, thereafter indentified as Neurospora sitophila, has the highest activity of 1,3-glyceride-specific lipase. The lipase of N. sitophila was able to catalyze glycerolysis of triacylglycerol (TAG) in CPO to produce DAG. The bioconversion products of lipase yielding ratio of DAG/TAG was higher than ratio of free fatty acids (FFA)/TAG (0.12 > 0.08). The optimum condition of the enzymatic bioconversion was at 40 oC, pH 6, and 10-day incubation. The primary fatty acids on the DAG were oleic (56.2%), palmitic (40.0%), and myristic (2.7%) acids. The decrease of palmitic acid on DAG compared to on TAG, indicated that the lipase of N. sitophila worked relatively specific at C1 or C3 of the TAG.Kurang berkembangnya industri hilir yang menghasilkan minyak khusus yang nilainya berlipat dibandingkan CPO antara lain karena hambatan teknis dan ketersediaan bahan pendukungnya. Lipase spesifik 1,3-gliserida misalnya, yang digunakan untuk produksi minyak kesehatan, masih diimpor dengan harga relatif tinggi. Minyak kesehatan dapat diproduksi dari biokonversi CPO dengan lipase spesifik 1,3-gliserida hingga diperoleh minyak yang kaya kandungan diasilgliserol (DAG). Tulisan ini melaporkan optimasi aktivitas lipase spesifik 1,3-gliserida dari fungi isolat lokal terpilih. Berdasarkan zona fluoresens pada medium penapis lipase, dari 20 isolat fungi yang diuji isolat P6 yang kemudian diidentifikasi sebagai Neurospora sitophila memiliki aktivitas tertinggi dan bersifat spesifik 1,3-gliserida. Lipase N. sitophilamampu mengkatalisis gliserolisis triasilgliserol (TAG) dalam CPO untuk menghasilkan DAG. Lipase tersebut menghasilkan nilai perban-dingan DAG/TAG lebih besar dari nilai perbandingan asam lemak bebas (ALB)/TAG (0,12 > 0,08). Kondisi optimum biokonversi enzimatis ini terjadi pada suhu 40 oC, pH 6, dan waktu inkubasi selama 10 hari. Asam lemak utama penyusun DAG adalah asam oleat (56,2%), palmitat (40,0%), dan miristat (2,7%). Berkurangnya asam palmitat pada DAG dibanding pada TAG menunjukkan bahwa lipase N. sitophila bekerja secara relatif spesifik pada C1 atau C3 dari gliserida.
PendahuluanPencemaran logam berat akhir-akhir ini menjadi perhatian penting di berbagai negara terkait dengan makin meningkatnya standar keamanan pangan (food safety) yang merupakan salah satu komponen dari ketahanan pangan (food security) (Badan Ketahanan Pangan 2013). Logam berat seperti timbal, tembaga, dan seng yang dihasilkan oleh limbah industri telah menyebabkan pencemaran cukup berat di Sungai Siak, Pekanbaru sehingga berbahaya untuk air minum, prasarana/ sarana rekreasi air, pembudidayaan ikan air tawar, peternakan dan pengairan lahan pertanian (Agustina et al., 2012). Logam berat seperti merkuri, kadmium, dan tembaga dalam konsentrasi cukup rendah (25-50 ppm) dapat menekan dan mematikan bakteri tanah bermanfaat seperti Azotobacter spp. (Luqman et al., 2012). Logam berat dalam konsentrasi relatif sangat kecil akan terserap oleh organisme tingkat rendah seperti plankton dan akan terbawa dalam rantai makanan hingga terakumulasi pada tubuh manusia (Mawardi 2007).Akumulasi logam berat dalam tubuh dapat menyebabkan gangguan serius pada syaraf otak, ginjal akut, kelainan janin, dan memicu kanker karena bertindak sebagai karsinogen melalui mekanisme oksidatif menghasilkan radikal bebas dan spesies oksigen reaktif menyerang dan merusak DNA sehingga gen-gen serta enzim penting lainnya tidak aktif (Misra et al., 2010).
Summary Concentrated latex effluent had not been economically utilized, consequently it had become source of environmental pollution and conflicts with surrounding community. Whereas, the concentrated latex effluent could be used as substrate for microbes growth media due to its high concentration of carbon and nitrogen. One of the economical benefits of growing Rhizobium sp. in this waste is the production of indole acetic acid (IAA) that can be used for plant promotion growth. The aims of this research were to get the optimal IAA production of Rhizobium sp. by optimizing its tryptophan supplementation through hydrolysis of chicken manure and to purify IAA produced using chromatographic method. The use of chicken manure directly caused the browning effect, therefore these experiments were carried out the variation of NaOH 2 N hydrolysis treatments to reduce the effect. Direct hydrolysis as the first media was obtained by mixing latex serum and manure, and then this mixture was hydrolyzed. Meanwhile, separated hydrolysis was done by adding water to manure, being hydrolyzed, and divided to become second and third media. The second media was made by mixing manure hydrolysate and latex serum directly, whereas in third media, hydrolisate was added with alum as coagulating agent. Rhizobium sp. was then inoculated to all media and incubated for 24, 48, and 72 hours in 27-30oC. IAA was analyzed by spectrophotometric method with Salkowsky reagent and Thin Layer Chromatography (TLC). IAA was then extracted with ethyl acetate and purified with silica gel column chromatography. The separated hydrolysis without coagulation (second media) produced the highest IAA concentration, that is 14.40 mg/mL, whereas IAA produced by direct hydrolysis (first media) was 14.13 mg/mL and 0.90 mg/mL for third media during 48 hours. The fractionation result for each mediums showed that the highest IAA distribution in first media was the 12th fraction (38.70%), meanwhile in second media was the 15th fraction (50.25%) and in the third media was the 13th fraction (26.16%). Ringkasan Limbah lateks pekat saat ini belum di-manfaatkan secara ekonomis, bahkan menjadi sumber pencemaran lingkungan dan konflik dengan masyarakat sekitarnya. Padahal limbah lateks pekat dapat digunakan sebagai substrat pertumbuhan mikroba karena memiliki kandungan karbon dan nitrogen yang cukup tinggi. Salah satu nilai ekonomis yang dapat diperoleh dengan ditumbuhkannya Rhizobium sp. pada limbah tersebut, yaitu dihasilkannya asam indol asetat (indol acetic acid/IAA) yang dapat digunakan untuk memacu pertumbuhan tanaman. Penelitian ini bertujuan memperoleh produksi IAA optimal yang dihasilkan Rhizobium sp. dengan asupan triptofan dari hidrolisis pupuk kandang dan memurnikan IAA yang dihasilkan tersebut dengan metode kromatografi. Penggunaan pupuk kandang secara langsung menyebabkan efek pen-cokelatan, maka dilakukan variasi perlakuan hidrolisis dengan NaOH 2 N untuk mengurangi efek tersebut. Hidrolisis langsung sebagai medium pertama diperoleh dengan mencampur serum lateks dan pupuk kandang, sedangkan hidrolisis terpisah dilakukan dengan menambah pupuk kandang dengan air, dan dibagi menjadi medium kedua dan ketiga. Medium kedua dibuat dengan cara langsung mencampur hidrolisat dan serum lateks, sedangkan pada medium ketiga, hidrolisat diendapkan dengan alum sebagai bahan pengendap. Kemudian ke dalam masing-masing medium diinokulasi Rhizobium sp. dan diinkubasi selama 24 ,48, dan 72 jam pada suhu 27-30oC. Analisis IAA dilakukan secara spektrofotometri dengan metode Salkowski dan Kromatografi Lapis Tipis (KLT). IAA diekstraksi menggunakan etil asetat dan dimurnikan dengan kromatografi kolom silika gel. Hidrolisis terpisah tanpa pengendapan (medium kedua) menghasilkan IAA tertinggi, yaitu 14,40 mg/mL, sedangkan hidrolis langsung (medium pertama) menghasilkan IAA sebesar 14,13 mg/mL dan medium ketiga sebesar 0,90 mg/mL selama 48 jam. Hasil fraksinasi untuk masing-masing medium menunjukkan sebaran IAA tertinggi pada medium pertama berada pada fraksi ke-12 (38,70%), sedangkan pada medium kedua pada fraksi ke-15 (50,25%), dan pada medium ketiga ialah fraksi ke-13 (26,16%).
SummaryIncreasing unsaturation level of crude oilpalm (CPO) could be carried out by usingdesaturase enzyme of Absidia corymbifera. Thisbiocatalyst could also produce polyunsaturatedfatty acids (PUFA) such as gamma linolenic acidthat beneficial for healthy oil. The objective ofthis research was to determine the optimumcontact time and ratio of immobilized desaturaseenzyme-substrate in batch system at semi pilotscale (5,000-15,000 mL). Desaturase wasextracted from A. corymbifera biomass andimmobilized on activated zeolite (3-6 mm).Immobilized enzymes were then used forbioconversion process in batch system by mixingthe enzyme with CPO in a bottle placedhorizontally then rotated using a rotator machineat room temperature (25-30 o C). The resultshowed that optimum contact time with ratioimmobilized enzyme-substrate 1:1; 1:2; and 1:3were 30, 40, and 50 min resulted in increasingiodine number 2.84; 3.94; and 4.46 g I 2 /100 gCPO, respectively. An optimum enzyme-subtrateratio was achieved at 1:2, resulted in increasingof iodine number 9-11 g I 2 /100 g CPO, productrecovery of 17,000 mL (21 batches) up to 18 hours. It was detected that active desaturasesduring CPO bioconversion were 6 , 9 , and 12 desaturases as shown by the increase of oleic(4.5%), linoleic (0,85%) and linolenic acids(60.7%).RingkasanPeningkatan ketidakjenuhan minyak sawitkasar (crude palm oil, CPO) dapat dilakukandengan enzim desaturase Absidia corymbifera.Biokatalis ini juga mampu menghasilkan asamlemak tidak jenuh majemuk (polyunsaturatedfatty acids, PUFA) yang bermanfaat untukkesehatan seperti asam gamma linolenat (GLA).Tujuan penelitian adalah menetapkan waktukontak dan nisbah enzim desaturase amobil-substrat optimum dalam sistem curah pada skalasemipilot (5.000-15.000 mL). Desaturase di-ekstraksi dari biomassa A. corymbifera dandiamobilisasi pada zeolite (3-6 mm) yang telahdiaktivasi. Enzim amobil kemudian digunakanuntuk proses biokonversi dalam sistem curahdengan cara mencampurkan dengan CPO dalambotol yang diletakkan secara horizontal kemudiandiputar dengan mesin rotator pada suhu ruang(25-30 o C). Hasil penelitian menunjukkan bahwawaktu kontak optimum enzim desaturase-substratdengan nisbah 1:1; 1:2; dan 1:3 adalah 30, 40,dan 50 menit dan menghasilkan peningkatanbilangan iod berturut-turut sebesar 2,84; 3,94;dan 4,46 g I 2 /100 g CPO. Nisbah enzim-substratoptimum dalam proses biokonversi CPO adalah1:2 yang menghasilkan peningkatan bilangan iod9-11 g I 2 /100 g CPO dan perolehan produk17.000 mL (21 kali curah) selama 18 jampemakaian. Penelitian juga dapat mendeteksibahwa desaturase yang aktif selama prosesbiokonversi CPO adalah 6 , 9 , dan 12desaturase yang ditunjukkan oleh peningkatanasam oleat (4,5%), linoleat (0,85%) dan linolenat(60,7%).
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