Judul: Telaah Aktivitas Bakteri Penghasil Lipase yang Berasosiasi dengan Tempe.
Abstrak: Tempe is known as fermented food products the origin of Indonesia. In addition as high nutritional value of foodstuffs, tempe is also known as the ecosystem for many types of microorganisms. Total fat content on tempe shows a decrease when compared to the fat content in soybean without fermentation. A decrease in fat levels in tempe is becoming an indicator of existence of lipolytic microorganisms in it. The existence of lipolysis activity in tempe make it more easy to digest and have a distinctive scent of the hydrolysis of the fatty acids. The sample was the traditional foods origin of Indonesia namely tempe. Tempe was collected from various of tempe craftsmen with specific of sample selection category. Observation of physical condition, consistency and aroma of tempe were done during several observation time span after sample collection. Samples of tempe have been observed subsequent of total bacterial population and lipase producing bacteria (lipolytic). The method is the standard plate count which plate count agar medium for enumeration of total bacterial population and Luria- Bertani agar medium emulsified with olive oil and rhodamine B for enumeration of lipolytic bacteria. The role of lipolytic bacteria in the flavour development of tempe also examined in briefly based on the content of free fatty acid profiles were analyzed by gas chromatrography with flame ionizer detector (GC-FID) method. The collection of samples obtained from three different tempe craftsmen in Bogor, hereinafter referred to as CMG, EMP and RTI. The all of those three distinguishing criteria of tempe sample based on cleanliness during the process of tempe production. Changes in physical condition, consistency and aroma of the tempe shows the difference on each type of tempe. The changes observed during the fastest observations occurred in tempe CMG followed by tempe EMG and slowest changes occur in tempe RTI. Total bacteria and lipolytic bacterial populations were carried out employing standard plate count method and showed CMG harbored the highest bacterial population number 2.31 × 109 cfu g-1 followed by EMP 9.78 × 108 cfu g-1 and RTI 4.04 × 106 cfu g-1. Lipolytic bacteria were found in each tempe samples which were approximately 0.1 % of total bacterial population. CMG harbored the highest lipolytic bacterial population number 1.04 × 106 cfu g-1 followed by EMP 2.88 × 105 cfu g-1 and RTI 1.72 × 104 cfu g-1. Tempe aroma and texture showed strong correlation between the numbers of bacterial population during the period or stages of tempe maturation. Moreover, we also found a unique correlation between dynamic of lipolytic population and flavor development. Free faty acid composition on tempe CMG, EMP and RTI are dominated by linoleic, oleic, palmitic, linolenic and stearic acid respectively.
Keyword: tempe, flavor development, lipolytic bacteria, GC-FID, free fatty acid

Judul: Analisis metagenom untuk pencirian komunitas bakteri dan fungi pada tempe
Abstrak: Tempe is an Indonesian traditional fermented food produced using Rhizopus as a starter culture. In practice, however, the starter culture as well as fermentation processes would involved a polymicrobial fermentation, which generated a unique tempe flavor and texture. This condition makes Indonesian tempe as one of the most complex fermented food, while at the same time would make it difficult to scale up tempe production with uniform quality and consistency. Because of complex microbial communities involved, cultureindependent methods or metagenomic analysis would be an essential tool to unravel this complex microbial fermentation. The aim of this study was to compare a number of tempe microbial communities based on Amplified Ribosomal Intergenic Sequence Analysis (ARISA). Fresh tempe samples were obtained from tempe producers in Java and Moluccas. 16S rRNA gene libraries and DNA sequencing were employed to analyze further the nature of microbial diversity in two selected tempe samples. The results of our study showed that different tempe producer possessed different Bacterial ARISA (BARISA) or fungi ARISA (FARISA) profiles. However, BARISA profiles were found to be more discriminative than FARISA, and therefore BARISA would be more useful for tempe genetic fingerprint or barcoding. Bacterial communities in two tempe samples (EMP and SDJD) were further investigated employing DNA sequence analysis of their 16S rRNA gene libraries. Sequences closely related to Klebsiella sp were found to be the majority among bacterial communities present in SDJD sample, while sequences closely related to Acetobacter sp. were found as predominant isolates in EMP samples. These significant differences in bacterial communities might reflect differences in tempe flavor or texture associated with their unique production or locality.
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf