PENGGUNAAN BAKTERI DAN JAMUR PENDEGRADASI LIGNOSELULOSA SALURAN PENCERNAAN HERBIVORA UNTUK MENINGKATKAN KECERNAAN SERAT KASAR

Ahmad Wahyudi, Ir.,M.Kes., Prof. Dr. Ir. Zaenal Bachruddin, M.Sc.,

2012 | Disertasi | S3 Bioteknologi

Kecernaan serat kasar di dalam rumen sapi yang dipelihara secara intensif umumnya rendah. Kondisi tersebut disebabkan karena mikrobia pendegradasi serat rumen mengalami penurunan populasi dan kemampuan. Penelitian ini dilakukan untuk memperoleh isolat bakteri dan jamur unggul pendegradasi lignoselulosa yang diisolasi secara anaerob dari saluran pencernaan kerbau, kuda, dan feses gajah. Bakteri pendegradasi lignoselulosa diisolasi menggunakan metode Hungate, sedangkan jamur diisolasi menggunakan metode Rao. Lignin/asam tanat, xilan, dan selulosa digunakan sebagai substrat. Seleksi isolat bakteri dan jamur pendegradasi lignoselulosa dilakukan secara kualitatif dan kuantitatif. Analisis kualitatif ditentukan berdasarkan rasio aktivitas isolat, yaitu perbandingan antara diameter zona difusi atau zona jernih dengan diameter koloni, sedangkan analisis kuantitatif berdasarkan aktivitas enzim pendegradasi lignin, xilan, dan selulosa. Hasil penelitian menunjukkan bahwa isolat bakteri dan jamur pendegradasi lignoselulosa dapat diperoleh dari seluruh sampel saluran pencernaan kerbau, kuda, dan feses gajah. Jumlah sel bakteri dan jamur pendegradasi lignoselulosa terbanyak keduanya diperoleh dari kolon kerbau dengan jumlah masing-masing adalah 7,5 x 10 8 dan 7,2 x 10 6 cfu/g sampel segar. Rasio aktivitas isolat bakteri pendegradasi lignin dan xilan menunjukkan perbedaan sangat nyata (P ≤0,01) dan pendegradasi selulosa berbeda nyata (P≤0,05) antar fragmen saluran pencernaan. Rasio aktivitas isolat bakteri pendegradasi lignin, xilan, dan selulosa tertinggi masing-masing diperoleh dari sekum kerbau sebesar 7,67, sekum kuda 6,28 dan kolon kerbau 2,39, sedangkan rasio aktivitas isolat jamur menunjukkan perbedaan tidak nyata. Aktivitas enzim bakteri pendegradasi lignin dan xilan menunjukkan perbedaan sangat nyata (P≤0,01) namun pendegradasi selulosa tidak menunjukkan perbedaan. Aktivitas enzim isolat bakteri pendegradasi lignin potensial diperoleh dari feses gajah dan sekum kerbau masingmasing sebesar 0,35 dan 0,24 U/mg protein, pendegradasi xilan tertinggi dari sekum kuda sebesar 33,48 U/mg protein. Aktivitas enzim isolat jamur pendegradasi lignin, xilan, dan selulosa seluruhnya menunjukkan perbedaan tidak nyata. Hasil identifikasi isolat bakteri potensial pendegradasi lignoselulosa diperoleh dua spesies, yaitu Wautersia paucula, dan Enterococcus casseliflavus, sedangkan isolat jamur hanya diperoleh satu genus yaitu Aspergillus sp. Penambahan isolat bakteri dan jamur pendegradasi lignoselulosa in vitro secara umum dapat meningkatkan kecernaan serat kasar (SK), neutral detergent fiber (NDF),dan acid detergent fiber (ADF) jerami padi. Penambahan isolat tunggal bakteri Enterococcus casseliflavus menghasilkan peningkatan paling optimal yaitu sebesar 20,08% SK, 14,04% NDF, dan 7,78% ADF. Penggunaan Enterococcus casseliflavus pada ensilase tanaman padi berpengaruh menurunkan kandungan ADF dan meningkatkan NDF serta sukrosa.

In general, crude fiber digestibility in cattle that intensively raise is low due to amount of microbial population and ability are decrease. This study was conducted to obtain superior lignocellulose-degrading bacteria and fungi isolated from buffalo’s and horse’s gastrointestinal tract and elephant’s feces and implement them on in vitro digestibility and on ensilage preparation. The bacteria were isolated anaerobically by Hungate methods, meanwhile fungus were isolated by Rao methods. Lignin/tanic acid, xylan, and cellulose were used as substrates. Lignocellulose degrading activity was determined by qualitative and quantitative analysis. Qualitative analysis was measured based on the ratio of diffusion or clear zone diameter with colony diameter, meanwhile quantitative analysis was done by measured of enzyme activity. The best isolates of bacteria and fungi were determined and implemented for in vitro fiber degestion and ensilage preparation. The result showed that lignocellulose-degrading bacteria and fungi could be isolated from all samples of swamp buffalo and horse digestive’s tract, and also elephant’s feces. The highest number of bacteria and fungi were found from buffalo’s colon as much as 7.5 x 10 8 and 7.2 x 10 6 cfu/g fresh matter respectively. Activity ratio of lignin and xylan-degrading isolates showed very significantly different (P≤0. 01), meanwhile cellulose-degrading isolate was significant (P ≤0. 05). The highest activity ratio of lignin, xylan, and cellulose-degrading bacteria respectively were found from buffalo’s cecum (7.67), horse’s cecum (6.28), and buffalo’s colon (2.39), meanwhile for fungi there were not significant different among isolates from all digestive’s tract compartement. Enzyme activities of lignin and xylan-degrading bacteria showed significanly different (P≤0.01) but for cellulose was not different. The superior value of lignin-degrading bacteria were found from elephant’s feces (0.35U/mg protein) and buffalo’s colon (0.24U/mg protein), meanwhile for xylan-degrading bacteria was 33.48 U/mg protein from horse’s cecum. All of enzyme activities of lignin, xylan, and cellulose-degrading fungi showed not significantly different. There were two best species of bacteria based on morphological characterization, i.e. Wautersia paucula (W. paucula) and Enterococcus casseliflavus (E. casseliflavus), and was Aspergillus sp. for fungi. It can be concluded that addition of all bacteria and fungi isolates were able to increase crude fiber (CF), neutral detergent fiber (NDF), and acid detergent fiber (ADF) of rice straw in vitro digestibilities. The most optimal for increasing fiber digestion was reached by E. casseliflavus addition that increased 20.08% CF; 14.04% NDF; 7.78% ADF respectively. Addition of E. casseliflavus in whole rice crop silages decreased ADF content, and very significantly increased NDF and sucrose content.

Kata Kunci : Bakteri, Jamur, Degradasi lignoselulosa, Herbivora, Kecernaan serat