Judul: Penelitian untuk Aplikasi Mobile Munsell Soil Color Chart Berbasis Android Menggunakan Histogram Ruang Citra HVC dengan Klasifikasi k-NN
Abstrak: Soil color determination is a challenging task because of the various types of soil and the high similarity of soil color. Munsell Soil Color Chart (MSCC) is used to overcome this issue. The purpose of this research is to develop an androidbased mobile application to identify the major color of soil according to MSCC. The application utilized HVC color model with hue, value, and chroma color components. The hue color component had been the main concern of this research, although the value and chorma color components were also observed. The training data were 259 images from MSCC, with 1600 pixels each. Hue color data from these pixels were analyzed in the form of histogram and classified with k-NN. The results showed that the highest classification accuracy of hue value was 45% at k=5, this accuracy may be improved by utilizing the soil color data that are available online.
Keyword: Munsell Soil Color Chart., k-NN, HVC, Android, Bogor Agricultural University (IPB)

Judul: Aplikasi Bagan Warna Daun untuk Optimasi Pemupukan Tanaman Padi Menggunakan k-Nearest Neighbor
Abstrak: The leaf color of rice is closely associated with the adequacy of nitrogen (N) level of the ground. N deficiency symptoms that are most obvious and commonly seen is the reduction of green color of the leaf. This research developed a mobile application to identify the color of rice leaf and to determine the appropriate fertilizer. The application was built by using the histogram feature of several color components namely Red, Green, Blue in the RGB color space, Hue, Saturation Value in the HSV color space, and grayscale. K-Nearest Neighbor was choosen as the classification method. This research showed the highest average accuracy of 90.63% on the G (green), V (Value) and grayscale color component. The k-NN classification method produced the highest average accuracy of 72.62% when the value of k is equal to 3.
Keyword: Android, grayscale, histogram, HSV, color identification, k-Nearest Neighbor

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