Judul: Perbandingan Kinerja Pemilihan Fitur Chi-square Dan Singular Value Decomposition Sistem Temu Kembali Dokumen Tumbuhan Obat
Abstrak: This study analyzes the performance of the chi-square feature selection and Singular Value Decomposition (SVD) document retrieval system medicinal plants. The method is to find an effective document retrieval system based on queries to produce documents relevant to the user. Chi-square selection techniques make the selection based on the features that are important words that are used to create a vector space models. The model consists of several documents represented as vectors of the frequency of occurrence of features. SVD feature selection technique using key words found in each document. Important words become terms of the term-document matrix. Indonesian language document medicinal plants totaling 132 documents used in the chi-square retrieval and SVD. Retrieval and SVD chi-square test with 29 non-semantic and semantic query. The result is a comparison of the performance of the retrieval of both methods on non-semantic and semantic query.
Keyword: chi square, singular value decomposition, information retrieval, eature selection, medicinal plants

Judul: Ekstraksi Ciri Dokumen Tumbuhan Obat Menggunakan Chi-Kuadrat dengan Klasifikasi Naive Bayes
Abstrak: This research presented a system for extracting terms and classifying medicinal plants documents using chi-square and naïve bayes classifier. Term extraction technique was used to make the classifier work efficiently and to increase classification accuracy. The criteria used in this research were the family of medicinal plants and utilization of medicinal plants for medication. The classification results were used to build an information retrieval system of Indonesian medicinal plants. This research used two significance levels for generating critical value, i.e 0.001 and 0.01. The experiment result showed that the critical value using significance level of 0.001 has better accuracy than the critical value using significance level 0.01. Accuracy of classification system using significance level of 0.001 were 97.44% for family and 89.74% for utilization of medicinal plants criteria. The information retrieval system tested using 29 queries about family and utilization of medicinal plants. The information retrieval system had an average value generated was 93.26%.
Keyword: 

Judul: Extracellular Expression of thermostable Geobacillus stearothermophilus T1.2RQ Lipase for Biodiesel Production
Abstrak: The extracellular expression of enzymes in an excellent secretion host such as Bacillus subtilis is a useful strategy for making enzymes of industrial significance more affordable by lowering the cost of its downstream processing. Lipases are a category of hydrolases that catalyze the hydrolysis of triglycerides to glycerol and free fatty acids. Also, lipases catalyze the hydrolysis and transesterification of other esters as well as the synthesis of esters. They can perform very specific biotransformation reactions and are widely used in food, organic synthesis, detergents, cosmetic, and pharmaceutical industries. Geobacillus stearothermophilus T1.2RQ lipase is an industrially-desired thermostable lipolytic enzyme with an excellent hydrolytic and transesterification activity. This study aimed to express T1.2RQ lipase, in B. subtilis WB800 and ensure its secretion into the extracellular medium. Three signal peptides (AmyQ, Epr, LipA) and two promoters (Pgrac01 and Pgrac100) were used in the secretory-expression of T1.2RQ lipase, based on five constructed expression vectors constructed by restriction cloning and PCR mutagenesis. Sangers sequencing was used to verify constructs to ensure they are in the correct reading frame. Recombinants vectors, pHT43 (plasmid control), pHT43-T1.2RQ, pHT43- T1.2RQ_AmyQ, pHT43-T1.2RQ_Epr, and pHT43-T1.2RQ_LipA, were transformed by electroporation into Bacillus subtilis WB800. The electroporation was successful with the optimum condition of 2500V, 200 ohms, 25µF, and 5milliseconds. Recombinant B. subtilis pHT43 (negative control) and pHT43-T1.2RQlip + signal peptides were streaked on the lipidic agar, LA+TBN. All four recombinants, including the negative control (B. subtilis WB800-pHT43), produced clear zones on the TBN agar plate after overnight incubation (fig 2), indicating the presence of a lipolytic enzyme in all of the recombinant B. subtilis cells. pHT43-T1.2RQlip + signal peptides (AmyQ, Epr, and LipA) have clear zones with significantly higher diameters than B. subtilis WB800-pHT43 (negative control). This phenomenon suggests that the recombinant thermostable lipase T1.2RQ introduced into these cells was successfully expressed, thereby increasing the lipolytic capability of its host cells T1.2RQ lipase was expressed in 50ml terrific broth medium (TB) and the expression induced with 1mM IPTG. Lipase activity assay using p-nitrophenyl esters showed that all three signal peptides directed the secretion of T1.2RQ lipase into the extracellular medium. Signal peptide, LipA, resulted in the highest extracellular activity of 5.6 U/mL, which corresponds to a 6-fold increase over the parent B. subtilis WB800 strain. Meanwhile, signal peptides, AmyQ and Epr produced 4.2 U/mL and 3.4 U/mL activity respectively. SDS-Zymogram analysis confirmed that T1.2RQ lipase was correctly processed and secreted in its original size of 44 kDa. An attempt to further increase lipase expression level by promoter optimization showed that, contrary to expectation, promoter Pgrac100 exhibited similar expression levels as the original Pgrac01. Nevertheless, the demonstration of the successful secretion of T1.2RQ lipase in this work confirms the latter as a promising approach for the industrial production of the enzyme
Keyword: Bacillus subtilis, Expression, Extracellular, Heterologous, Lipase, Thermostable