Judul: Production of ß-1,3-Glucanase Enzyme from  Streptomyces sp. Antifungal Phytopathogens on Several Mediums and  Determination of its Activity
Abstrak: Enzim ß-1,3-glukanase merupakan enzim hidrolitik yang mampu mendegradasi ß-glukan penyusun dinding sel cendawan fitopatogen. Enzim ini dapat diproduksi Streptomyces tritolerans ARJ 32 dan Streptomyces collinus ARJ 38 dan berpotensi sebagai fungisida alami. Namun, produksi enzim ini membutuhkan media produksi yang relatif mahal. Oleh karena itu, penelitian ini bertujuan memproduksi enzim ß-1,3-glukanase dari S. tritolerans ARJ 32 dan S. colinus ARJ 38 antifungi fitopatogen pada beberapa medium dan menentukan aktivitasnya. Kuantifikasi aktivitas enzim ß-1,3-glukanase menunjukan nilai aktivitas tertinggi kedua Streptomyces sp. yang dikulturkan di media ekstrak ubi jalar, yakni sebesar 32,970 U/mg (S. tritolerans ARJ 32) dan 80,410 U/mg (S. collinus ARJ 38). Nilai aktivitas enzim ß-1,3-glukanase ini menunjukkan bahwa ekstrak ubi jalar berpotensi digunakan sebagai media alternatif produksi enzim ß-1,3-glukanase. Streptomyces sp. memiliki aktivitas antifungi terhadap F. oxysporum dan R. solani dengan penghambatan 23,96% dan 32,52% (ARJ 32) dan 21,88% dan 37,40% (ARJ 38)., ß-1,3-Glucanase enzyme is a hydrolytic enzyme capable of degrading ß-glucan constituting fungi cell wall. This enzyme can be produced by Streptomyces tritolerans ARJ 32 and Streptomyces collinus ARJ 38 and has potential as a natural fungicide. However, the production of this enzyme requires relatively expensive ingredients. Therefore, this study aimed to produce ß-1,3-glucanase enzymes from S. tritolerans ARJ 32 and S. colinus ARJ 38 against phytopathogenic fungi on several media and determining their activity. Quantification of glucanase enzyme activity showed the highest activity of both Streptomyces sp. cultured in sweet potato extract broth media, with 32,970 U/mg (S. tritolerans ARJ 32) and 80,410 U/mg (S. collinus ARJ 38). These results shows that sweet potato extract is potentially an alternative media production for ß-1,3-glucanase enzyme production. Streptomyces sp. had antifungal activity against F. oxysporum and R. solani with inhibition of 23,96% and 32,52% (ARJ 32) and 21,88% and 37,40% (ARJ 38).
Keyword: antifungi, molase, Ubi jalar, enzim ß-1,3-glukanase, kentang

Judul: Production of ß-1,3-Glucanase Enzyme from  Streptomyces sp. Antifungal Phytopathogens on Several Mediums and  Determination of its Activity
Abstrak: Enzim ß-1,3-glukanase merupakan enzim hidrolitik yang mampu mendegradasi ß-glukan penyusun dinding sel cendawan fitopatogen. Enzim ini dapat diproduksi Streptomyces tritolerans ARJ 32 dan Streptomyces collinus ARJ 38 dan berpotensi sebagai fungisida alami. Namun, produksi enzim ini membutuhkan media produksi yang relatif mahal. Oleh karena itu, penelitian ini bertujuan memproduksi enzim ß-1,3-glukanase dari S. tritolerans ARJ 32 dan S. colinus ARJ 38 antifungi fitopatogen pada beberapa medium dan menentukan aktivitasnya. Kuantifikasi aktivitas enzim ß-1,3-glukanase menunjukan nilai aktivitas tertinggi kedua Streptomyces sp. yang dikulturkan di media ekstrak ubi jalar, yakni sebesar 32,970 U/mg (S. tritolerans ARJ 32) dan 80,410 U/mg (S. collinus ARJ 38). Nilai aktivitas enzim ß-1,3-glukanase ini menunjukkan bahwa ekstrak ubi jalar berpotensi digunakan sebagai media alternatif produksi enzim ß-1,3-glukanase. Streptomyces sp. memiliki aktivitas antifungi terhadap F. oxysporum dan R. solani dengan penghambatan 23,96% dan 32,52% (ARJ 32) dan 21,88% dan 37,40% (ARJ 38)., ß-1,3-Glucanase enzyme is a hydrolytic enzyme capable of degrading ß-glucan constituting fungi cell wall. This enzyme can be produced by Streptomyces tritolerans ARJ 32 and Streptomyces collinus ARJ 38 and has potential as a natural fungicide. However, the production of this enzyme requires relatively expensive ingredients. Therefore, this study aimed to produce ß-1,3-glucanase enzymes from S. tritolerans ARJ 32 and S. colinus ARJ 38 against phytopathogenic fungi on several media and determining their activity. Quantification of glucanase enzyme activity showed the highest activity of both Streptomyces sp. cultured in sweet potato extract broth media, with 32,970 U/mg (S. tritolerans ARJ 32) and 80,410 U/mg (S. collinus ARJ 38). These results shows that sweet potato extract is potentially an alternative media production for ß-1,3-glucanase enzyme production. Streptomyces sp. had antifungal activity against F. oxysporum and R. solani with inhibition of 23,96% and 32,52% (ARJ 32) and 21,88% and 37,40% (ARJ 38).
Keyword: antifungi, molase, Ubi jalar, enzim ß-1,3-glukanase, kentang

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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