Judul: Isolation and Selection of Chitosanolytic and Cellulolytic Endophytic Fungi from Different Seaweeds
Abstrak: Oligokitosan sebagai oligomer kitosan telah banyak dimanfaatkan untuk berbagai aplikasi biologis. Oligokitosan dapat diproduksi dengan metode enzimatis. Produksi oligokitosan dengan depolimerisasi kitosan secara enzimatis membutuhkan penggunaan enzim spesifik seperti kitosanase atau non-spesifik seperti selulase yang dapat diperoleh dari kapang endofit yang bersimbiosis dengan biota laut. Penelitian bertujuan mendapatkan isolat, mengkarakterisasi dan menyeleksi kapang endofit dari rumput laut dengan aktifitas kitosanolitik dan selulolitik, serta identifikasi kapang endofit yang potensial menghasilkan enzim kitosanolitik dan selulolitik. Penelitian dilakukan dengan tahapan isolasi, penapisan aktivitas enzim, identifikasi morfologi dan molekuler kapang endofit. Sebanyak 42 isolat kapang endofit berhasil diisolasi dari rumput laut. Satu isolat kapang memiliki aktivitas kitosanolitik dan berjumlah 24 isolat memiliki aktivitas selulolitik dengan kategori indeks selulolitik sedang hingga rendah. Secara molekuler, isolat kapang endofit kitosanolitik dan selulolitik teridentifikasi sebagai Neoantrodia serialis (KTR2), Trichoderma harzianum (KTR3, KTR4) dan Apiotrichum mycotoxinovorans (KTR1). Enzim kitosanolitik dan selulolitik kapang endofit rumput laut kedepannya dapat dikembangkan menjadi alternatif untuk produksi berbagai oligomer secara enzimatis, salah satunya yaitu oligokitosan., Oligochitosan as an oligomer of chitosan has been widely utilized for various biological applications. Oligochitosan can be produced by enzymatic methods. The production of oligochitosan by enzymatically depolymerizing chitosan requires the use of specific enzymes such as chitosanase or non-specific enzymes such as cellulase that can be obtained from endophytic fungi that are symbiotic with marine biota. The research aims to obtain isolates, characterize and select endophytic fungi from seaweed with chitosanolytic and cellulolytic activities, and identify endophytic fungi that have the potential to produce chitosanolytic and cellulolytic enzymes. The research was conducted with the stages of isolation, screening of enzyme activity, morphological and molecular identification of endophytic fungi. A total of 42 endophytic fungi isolates were successfully isolated from seaweed. One isolate had chitosanolytic activity and 24 isolates had cellulolytic activity with moderate to low cellulolytic index categories. Molecularly, the chitosanolytic and cellulolytic endophytic fungi isolates were identified as Neoantrodia serialis (KTR2), Trichoderma harzianum (KTR3, KTR4) and Apiotrichum mycotoxinovorans (KTR1). The chitosanolytic and cellulolytic enzymes of seaweed endophytic fungi can be developed into alternatives for the enzymatic production of various oligomers, one of which is oligochitosan.
Keyword: enzim, rumput laut, kapang endofit, kitosanolitik, selulolitik

Judul: Characterization of Cellulase from Marine Fungi RS6A and Its Application for Hydrolysis of Kappaphycus alvarezii
Abstrak: Hidrolisis secara enzimatis diketahui memiliki keunggulan diantaranya yaitu secara spesifik menghasilkan oligosakarida, ramah lingkungan dan tidak berpotensi meninggalkan residu toksik. Kapang RS6A dimanfaatkan dalam proses hidrolisis rumput laut K. alvarezii sebagai penghasil enzim selulase untuk memisahkan komponen lignoselulosa dan oligosakarida. Penelitian ini bertujuan menentukan pengaruh perbedaan waktu inkubasi dan konsentrasi CMC terhadap aktivitas selulase, menentukan waktu inkubasi dan konsentrasi CMC terbaik untuk produksi enzim selulase dan menentukan waktu hidrolisis rumput laut K. alvarezii menggunakan enzim selulase dari isolat kapang RS6A. Analisis data aktivitas selulase yang digunakan dalam penelitian ini adalah rancangan acak lengkap faktorial dua faktor. Konsentrasi sumber karbon dan waktu inkubasi yang menghasilkan aktivitas selulase optimum yaitu CMC 2% dan inkubasi enam hari. Ekstrak kasar selulase memiliki aktivitas selulase optimum sebesar 0,071±0,001 U/mL, aktivitas endoglukanase sebesar 0,197±0,035 U/mL, dan aktivitas spesifik selulase sebesar 0,088±0,009 U/mg. Hidrolisis selama 3 jam menghasilkan persentase hidrolisis selulosa sebesar 73% dan persentase hidrolisis lignin sebesar 4,8%., Enzymatic hydrolysis potentially offers many advantages, such as specific hydrolysis resulting in the production of target oligosaccharides, environmentally friendly and without produce toxic residual molecules. Fungi RS6A was applied in the hydrolysis of algae K. alvarezii as a cellulase enzyme producer to separated lignocellulose and oligosaccharide. The objectives of this research were to determine the effect of differences in incubation time and concentration of CMC on cellulase activity, determine the best incubation time and concentration of CMC for cellulase enzyme production and determine the hydrolysis time of K. Alvarezii. Data analysis of cellulase used in this research was completely randomized factorial design with two factors. The incubation time for 6 days and treatment of 2% CMC showed the highest cellulase activity of 0.071±0.001 U/mL, the highest endoglucanase activity of 0.197±0.035 U/mL and the highest specific cellulase activity of 0.088±0.009 U/mg. Hydrolysis for 3 hours showed cellulose hydrolysis degree of 73% and lignin hydrolysis degree was 4.8%.
Keyword: cellulase, hydrolysis, marine fung

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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