Judul: Production of Fruiting Body and Nutritional Content  of White Oyster Mushroom (Pleurotus sp.) of HS isolate on Coconut Coir and  Rice Straw Substrates
Abstrak: Jamur tiram putih (Pleurotus sp.) banyak dibudidayakan masyarakat karena memilki kandungan gizi yang tinggi dan biaya produksi yang cukup murah. Sabut kelapa dan jerami padi termasuk limbah pertanian yang mengandung selulosa, hemiselulosa dan lignin yang berpotensi digunakan sebagai substrat tumbuh jamur tiram. Penelitian ini dilakukan untuk mengamati pertumbuhan dan kandungan gizi Pleurotus sp. isolat HS dalam 500 gram media pada substrat yang berbeda yaitu jerami padi (JR), sabut kelapa (SK) serta campuran jerami padi dan sabut kelapa (JRSK). Fase vegetatif Pleurotus sp. HS pada SK (31 hari) lebih lama daripada JR (27 hari) dan JRSK (28 hari), sedangkan fase reproduktifnya pada substrat JR dan JRSK (17 hari) lebih lama daripada SK (12 hari). Efisiensi biologisnya pada JR (42%) dan JRSK (31,53%) lebih tinggi daripada SK (15,76%). Kadar abu, protein, dan lemak Pleurotus sp. HS pada substrat JRSK masing-masing 12,18%, 24,47%, dan 1,76% lebih tinggi daripada JR masing-masing 8,56%, 18,79%, dan 0,95%, sedangkan kadar seratnya pada JRSK (7,43%) lebih tinggi daripada SK (5,69%) dan lebih rendah daripada JR (10, 59%)., White oyster mushrooms (Pleurotus sp.) are widely cultivated by the community due to their high nutritional content and relatively low production costs. Coconut coir and rice straw are agricultural wastes that contain cellulose, hemicellulose, and lignin which can be potential to be used as substrates for growing oyster mushrooms. This study was conducted to observe the growth and nutritional content of Pleurotus sp. HS on different substrate combinations in 500 grams of media, namely Rice Straw (JR), coconut coir (SK), and a combination of rice straw and coconut coir (JRSK). The vegetative phase of SK (31 days) was longer than JR (27 days) and JRSK (28 days). The reproductive phase of JR and JRSK (17 days) was longer than SK (12 days). The biological efficiency of JR (42%) and JRSK (31,53%) is higher than SK (15,76%). The ash, protein, and fat content of JRSK (12,18%, 24,47%, and 1,76% respectively) were higher than JR (8,56%, 18,79%, and 0,95% respectively). The fiber content of JRSK (7,43%) is higher than SK (5,69%) and lower than JR (10,59%).
Keyword: biological efficiency, fiber content, protein, reproductive phase, vegetative phase

Judul: Coffee Ground and Husk as Components of Growing Media for the Production of White Oyster Mushroom (Pleurotus ostreatus)
Abstrak: Jamur tiram memiliki nilai ekonomi, ekologi, dan kesehatan serta dibudidayakan dengan media serbuk kayu dengan campuran dedak. Namun, pemanfaatan dedak bersaing dengan kebutuhan lain, seperti pakan. Padahal, limbah industri kopi banyak tersedia. Oleh sebab itu, penelitian ini bertujuan untuk mengetahui potensi ampas dan kulit kopi sebagai komponen media jamur tiram putih pengganti dedak. Penelitian dilakukan pada dua konsentrasi ampas dan kulit kopi (9% dan 18%), sehingga terdapat empat perlakuan: ampas kopi 9% (A1), ampas kopi 18% (A2), kulit kopi 9% (K1), dan kulit kopi 18% (K2). Media perlakuan ditambah serbuk gergaji 80%, kapur 2%, dan dedak 9% atau 0%. Media kontrol (K) memiliki dedak 18%. Jamur dipanen hingga tiga kali. Setiap perlakuan memiliki rasio C/N dan produksi yang berbeda. Media dengan rasio C/N tertinggi adalah K2, diikuti berturut-turut oleh A2, K1, A1, dan K. Media dengan rasio C/N yang lebih tinggi menunjukkan periode inkubasi yang lebih pendek, kecuali pada K1 dan K2. Sebaliknya, media dengan rasio C/N yang lebih rendah menunjukkan bobot panen total, bobot tubuh buah, jumlah tubuh buah dan primordium (kecuali pada K1), dan nilai efisiensi biologi (EB) yang lebih tinggi. Perlakuan A1 memiliki nilai keberterimaan yang baik dan EB 42.11%, sehingga ampas kopi 9% dapat menjadi alternatif pengganti dedak., Oyster mushrooms have economic, ecological, and health values and are cultivated with sawdust media with a mixture of rice bran. However, the use of rice bran competes with other needs, such as feed. Meanwhile, coffee industry waste is widely available. Therefore, this study aims to determine the potential of coffee grounds and skins as components of white oyster mushroom media to replace rice bran. The study was conducted at two concentrations of coffee grounds and husks (9% and 18%), so that there were four treatments: 9% coffee grounds (A1), 18% coffee grounds (A2), 9% coffee husks (K1), and 18% coffee husks (K2). Added with 80% sawdust, 2% lime, and 9% or 0% rice bran. The control medium (K) had 18% bran. Mushrooms are harvested up to three times. Each treatment has a different C/N ratio and production. The medium with the highest C/N ratio was K2, followed by A2, K1, A1, and K, respectively. The medium with the higher C/N ratio showed a shorter incubation period, except for K1 and K2. On the other hand, media with a lower C/N ratio showed higher total harvest weight, fruiting body weight, number of fruiting bodies and primordium (except for K1), and higher biological efficiency (EB) values. The A1 treatment had a good acceptability value and an EB of 42.11%, 9% coffee grounds could be an alternative to rice bran.
Keyword: antinutrition, biological efficiency, C/N ratio, utilization

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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