Selasa, 08 Mei 2018

Genome structure of Acetobacter aceti

Jual Culture Acetobacter aceti
Telp. 087731375234

Acetobacter aceti is a non-pathogenic, gram negative prokaryote that converts ethanol to acetic acid with the presence of oxygen, making it an obligate aerobe. This microbe is commonly known to the public as producing vinegar, wines, and beers. Acetobacter acetiis an aerobe and is also motile via peritrichous flagella. Acetobacter aceti is ubiquitous in nature and is everywhere there is fermentation occurring, growing optimally in a seven percent ethanol solution at thirty degrees Celcius. Acetobacter aceti is also known for its high tolerance of acidic conditions. Genome structure of Acetobacter aceti  are 3,340,429 total base pairs of DNA that make up the genome of Acetobacter aceti. There are a total of 3122 genes within Acetobacter aceti. 3050, or ninety seven percent of the genes all code for proteins, meaning that a large portion of Acetobacter aceti is to produce protein.

Cell and colony structure Acetobacter aceti  are rod shaped cells and can occur as individual cell pairs, chains, and small clusters units. The flagellum of Acetobacter acetiis arranged peritrichously. The cells can rotate their flagellum counter clockwise and clockwise in direction. Metabolism Acetobacter aceti  is an obligatory aerobic bacterium that can fix nitrogen during its metabolic processes and is known for producing alcohol as a byproduct of its metabolism. Acetobacter aceti uses sugars and alcohols for its carbon source and turns them into their acetic acid. The external electron source is nitrogen in the form of nitrite and nitrate and reduces them into ammonia and hydrogen. The primary molecule Acetobacter acetiproduces is acetic acid.

Acetobacter aceti is widespread in the environment; living in any environment where there is sugar present. This environment includes flowers, fruits, soil, and water. Acetobacter aceti contributes to the environment in many ways, metabolizing and breaking down foods such as fruits so that other animals can feed off its wastes and metabolize its byproducts. Acetobacter aceti has been utilized for the specifics of metabolizing sugars and releases its byproducts in the form of acetic acid, producing vinegar, a food product for us as humans to consume.

Pathology of Acetobacter aceti has yet to be reported as a pathogenic microbe to humans or animals. Acetobacter aceti does not produce any toxins, enzymes, or any viruses that harm any human or animal. Since Acetobacter aceti is ubiquitous in nature and there is contact of this bacterium on all animals on a frequent basis. Acetobacter aceti is not a portion of normal flora of bacteria on human skin. The only potential pathology it could present is if presented in mass quantities, an allergic or immune response could occur. Acetobacter aceti does produce alcohols, meaning if consumed in large quantities, these alcohols could affect the central nervous system, causing intoxication via alcohol, a byproduct of Acetobacter aceti, although alcoholism or intoxication is not due to the bacterium. Acetobacter aceti is known to cause rotting and browning discoloration in fruits such as apples, pears, and citrus products. Acetobacter aceti is known for causing pink disease in pineapple, which is the turning of the pineapple pink due to the metabolism of the pineapple by Acetobacter aceti along with the production of its waste.

Aspergillus sojae Vs Aspergillus oryzae

Jual Culture Aspergillus sojae & Aspergillus oryzae
Dalam Agar miring atau serbuk
Telp. 087731375234

Aspergillus sojae and Aspergillus oryzae play an important role in producing the distinctive taste of soy sauce by hydrolyzing soybean proteins. The molds secrete two kinds of metalloproteases, neutral proteinase I and neutral proteinase II (NpII). The neutral proteinase I has properties similar to those of Bacillus thermoproteolyticus thermolysin, an extensively characterized metalloprotease, while NpII has quite different substrate specificity, molecular mass and thermal stability. Gripon and colleagues characterized metalloproteases from Penicillium caseicolum and P. roqueforti, and suggested that these metalloproteases and NpII should be grouped under the term ‘acid metalloproteases’. These metalloproteases were classified as deuterolysin by the IUBMB in 1992.
Studies of A. oryzae and A. sojae strains used for shoyu production have focused on comparing these two fungal species and improving their enzyme-producing abilities. A study of the enzymatic differences between 11 strains of A. oryzae and 20 strains of A. sojae showed that the activities of neutral, acid, and alkaline proteases, xylanase, pectin lyase, phosphatase, and aminopeptidase were not significantly different. However, acid carboxypeptidase activity and α-amylase activity were higher from A. oryzae when compared with A. sojae strains, while endopolygalacturonidase activity was much higher from A. sojae than from A. oryzae (Terada et al., 1980). The ratios between α-amylase activity and endopolygalacturonidase activity of 0.5–2 for A. sojae and 20–2000 for A. oryzae were suggested as a differentiation criterion for the species (Terada et al., 1980). Hayashi et al. (1981) compared the performance of these two fungi in shoyu production. They found that the activities of protease, acetic carboxypeptidase, and α-amylase were lower and those of endopolyglueuronidase and glutaminase were higher in koji made with A. sojae.
In the moromi stage, the proportions of NH3 nitrogen (N), glutamic acid N, and total Ν were higher, and viscosity and heat residue were lower with A. sojae. The resulting concentrations of citric and succinic acids in the shoyu were significantly higher (p < 0.001) with A. sojae than with A. oryzae. Ishihara et al. (1996) compared the volatile components in commercial koikuchi shoyus from different factories using either A. oryzae or A. sojae and found that the concentrations of 1- and 2-propanol, furfuryl and benzyl alcohols, ethyl-benzoate, and lactate, acetate, pyrazines, carbonyl compounds such as ethanal, maltol, and phenyl acetaldehyde, phenol, and others, were higher in the shoyu from factories using the latter fungus, but concentrations of 2-methyl- and 3-methyl − 1-butanol, 2-phenyl ethanol, 2-methyl- and 3-methyl-butanoic acid, 3-methylthio − 1-propanol, HEMF, 4-ethyl guaiacol, 4-ethyl phenol, and others were greater in shoyu from factories using the former fungus. These results have prompted factory managements to use A. sojae for koji production.
Using an unusual system, Yasui et al. (1982) tested a range of koji fungal strains for glutaminase production and found that, when a strain showing 16% higher glutaminase activity than its parent strain was compared with its parent in the production of shoyu, the final glutamic acid concentration was 10% higher. In the early 1950s, A. sojae KS was irradiated with X-rays by Iguchi to produce strain X-816 of A. sojae (Sekine et al., 1970). Sekine et al. (1970) obtained seven strains with superior alkaline phosphatase activity (130–190%) and highly active protease, peptidase, cellulase, and amylase activities that were better at decomposing soybean protein. Yokoyama and Kadowaki (1983) UV-irradiated A. sojae strain Η and obtained mutant strains with total protease activities 2.5 times that in wheat bran and soy sauce kojis. The mutant strains were diploidized and combined with natural mutants from Μ strains, and strains TH and D-15 were produced that possessed higher total protease activities than the Μ strains, and grew well. However, UV irradiation may stimulate the production of toxic elements in otherwise safe fungi. Kalayanamitr et al. (1987) UV-irradiated A. flavus var. columnaris Raper and Fennel (ATCC44310) to obtain mutant strains with high protease and amylase activities, and light-colored conidia. Some selected mutant strains were found to be acutely toxic to weanling rats, even though they were negative for aflatoxin production. The investigators suggested that the toxic compound could be one of four substances: maltorhyzine, aspergillic acid, kojic acid, or cycoopiazonic acid.
Furuya et al. (1983) fused, with an efficiency of 1%, protoplasts derived from two strains of A. oryzae, one with a high growth rate and the other producing high levels of protease. Two strains derived from successful fusions showed high stability, fast growth, and abundant sporulation and produced 2.3 times more protease than the parent fast-growth strain. The growth and development of microorganisms on defatted soybean and ground wheat koji prepared with A. sojae were studied by electron microscopy by Kitahara et al. (1980). Growth of the mold on the surface of the soybean was rapid up to 24 h, at which point formation of sporing bodies began, and spores were released within 40 h. However, very little fungal growth was seen on the wheat surface, but yeasts were seen growing on the wheat. Growth of Micrococcus species became noticeable after 16 h, as did multiplication of lactobacilli. These observations on the growth of the koji mold are at odds with the observation that 10–20% of the dry matter in koji is lost in the koji stage (Takeuchi et al., 1968) and the observations below on the significant consumption of carbohydrate during the koji stage. I suggest that significant penetration of the wheat endosperm should have been seen.
During koji production, carbohydrate is consumed by the fungus, thus leaving less carbohydrate available to provide flavor compounds for the final shoyu produced (Furuya et al., 1985). This carbohydrate consumption is positively correlated with α-amylase activity in koji culture. To overcome the depletion of carbohydrate before the moromi stage, Furuya et al. (1985) derived mutants that utilized 10–50% less carbohydrate during preparation of koji than the parent strain, with about 1/3, 1/20, and 1/150 of the α-amylase activity of the parent strain of A. oryzae. Significantly increased amounts of carbohydrate-derived compounds were found in the resulting shoyu made with these mutants.
Enhanced glutaminase activity in koji is desirable to increase glutamic acid production in soy sauce, and reduced conidial production in the koji reduces contamination of the air with floating conidia (Ueki et al., 1994a). A mixed tane koji of two koji fungi, A. oryzae strains K2 and HG, increased glutaminase activity of the mixture to 11.3 units · g− 1 dry koji, which was higher than the 4.7 or 4.4 units · g− 1 dry koji produced by the K2 strain or HG strain, respectively, and conidia production was reduced tenfold (Ueki et al., 1994a). The mixed tane koji was used in the manufacture of soy sauce, and the resulting mixed koji made with 3.6 tons of defatted soybean and of wheat grain showed high glutaminase activity (5.5 units · g− 1 dry weight koji) when compared to strain K2 alone (1.8 units · g− 1 dry weight koji). In addition, the number of conidia in the mixed culture was 2.5 × 107 g− 1 dry koji, which was lower than 1.3 × 108 g− 1dry koji produced by strain K2 alone. The glutamic acid content of the raw soy sauce was 1.25 times higher than the glutamic acid level found in normal soy sauce (Ueki et al., 1994b).
Kim and Cho (1975) investigated soy sauce production in Korea using a soy–wheat koji prepared with A. sojae, using natto, a soy bean product prepared with Bacillus natto, and using a mixture of the two in varying proportions. The natto–brine mixture had protease activity twice as high as the koji alone, and this was reflected in the protease activities found in mixtures of the natto and koji. On comparing the organoleptic qualities of soy sauces fermented for 3 months, the koji:natto at a ratio of 6:4 had the best flavor, followed by koji alone.

Teknologi Mengolah Singkong Menjadi Nata De Casssava

Jual bakteri Acetobacter xylinum (bibit nata)
Telp. 087731375234

Singkong adalah salah satu komoditas pertanian unggulan Indonesia. Singkong telah banyak diolah menjadi aneka produk yang memiliki nilai ekonomis tinggi diantaranya adalah; tapioka, tepung mocaf, bioetanol, casapro, pakan ternak, dan berbagai aneka makanan camilan.  saat ini, singkong telah dikembangkan menjadi nata de cassava-bahan baku minuman kemasa. Pengolahan singkong menjadi nata de cassava merupakan temuan yang sangat bermanfaat bagi industri minuman karena bisa menjadi subtitusi  nat de coco yang kebutuhannya sangat tinggi. Industri minuman nata de coco memiliki permintaan yang sangat tinggi karena selain memiliki pasar domestik juga pasar manca negara. Kebutuhan pabrik minuman nata de coco masih belum terpenuhi secara maksimal, karena masih terkendala keterbatasan bahan baku air kelapa. Nata de cassava yang berbahan baku singkong memiliki keunggulan bahan baku yang melimpah dan karakteristik natanya tidak beraroma menyengat, serta lebih kenyal tidak terlalu alot.

Nata de cassava secara tampilan mirip dengan nata de coco yaitu berbentuk jel, warna putih, kenyal, berserat tinggi. Nata de cassava lebih lunak tidak alot, dan aroma nya tidak terlalu menyengat dibanding dengan nata de coco-nata berbahan baku air kelapa. Nata merupakan bahan baku produk minuman kemasan yang sudah sangat popular dan banyak disukai kalangan. Saat ini kebutuhan air kelapa untuk industi nata de coco semakin bersaing, seiring dengan tingginya permintaan nata de coco. Ketersediaa bahan baku singkong yang melimpah menjadi keunggulan tersendiri pengembangan industry nata de cassava sebagai subtitusi nata de coco. 

Urutan proses pembutan nata de cassava adalah sebagai berikut:
1. Pengupasan
Singkong yang telah ditimbang, kemudian dikupas dengan menggunakan pisau. Kemudian singkong yang telah dikupas ditampung dalam ember yang berisi air agar tidak terjadi penambahan asam sianida yang menyebabkan warna singkong menjadi biru dan berasa pahit.
2. Pencucian
Singkong yang telah dikupas, kemudian dicuci hingga bersih dengan menggunakan air yang mengalir.
3. Pemarutan
Proses pemarutan dilakukan dengan menggunakan mesin pemarut. Proses pemarutan dengan menggunakan mesin pemarut lebih efesien dan lebih cepat.
Singkong yang telah diparut kemudian diencerkan dengan penambahan air bersih kurang lebih 50 liter per 5 Kg umbi singkong yang telah dikupas. Air yang digunakan untuk pengenceran harus dengan menggunakan air yang bebas dari bahan kimia seperti kaporit atau tercemar bahan kimia lainnya.
5. Perebusan I
Tambahkan enzim αlfa-amilasi sebanyak 10-15 ml. Kemudian lakukan pengadukan sampai merata. Setelah mendidih, larutan diangkat kemudian pada saat proses pendinginan mencapai suhu kurang lebih 60-65˚C ditambahkan enzim gluco-amylase sebanyak 10-15 ml, biarkan sampai dingin kurang lebih 2-3 hari.
Setelah larutan menjadi dingin lakukan penyaringan dan pemerasan/pengepresan dengan menggunakan kain atau menggunakan alat pengepres mekanik.
7.Perebusan II
Larutan sebanyak 50 liter yang telah disaring dan dipisahkan ampasnya, kemudian direbus lagi. Kemudian tambahkan asam asetat sebanyak 200 ml. Setelah mendidih tambahkan ZA (ammonium sulfat) sebanyak 150 gram.
8.Fermentasi / inkubasi
Siapkan nampan bersih, tutup koran dengan diikat karet ban secara melingkar pada bagian tepi nampan, lalu susun pada rak. Jika media larutan singkong telah mendidih, kemudian buka salah satu bagian ujung nampan, tuangkan larutan dalam keadaan mendidih ke dalam nampan kemudian ditutup kembali dan diikat dengan tali karet ban, disusun tumpuk bersilangan hingga 6-8 nampan di rak. Setelah dingin, kemudian diinokulasi dengan penambahan bibit Acetobacter xylinum sebanyak 10 % atau kurang lebih 100-120 ml, biarkan hingga 8-10 hari.

Sabtu, 21 April 2018

Nutrient Agar Dan Nutrient Broth

Jual Media Nutrien Agara Dan Nutrient Broth
Dan Aneka Media Mikroba lainnya.
Telp. 087731375234

Nutrient agar (NA) adalah medium digunakan untuk menumbuhkan beberapa jenis mikroba yang tidak selektif yang secara umum bersifat heterotrof. Nutrient agar merupakan media sederhana yang dibuat dari ekstrak beef, pepton, dan agar. NA merupakan salah satu media yang umum digunakan dalam prosedur bakteriologi seperti uji biasa dari air, sewage, produk pangan, untuk membawa stok kultur, untuk pertumbuhan sampel pada uji bakteri, dan untuk mengisolasi organisme dalam kultur murni.
Untuk komposisi nutrient adalah eksrak beef 10 g, pepton 10 g, NaCl 5 g, air desitilat 1.000 ml dan 15 g agar/L. Agar dilarutkan dengan komposisi lain dan disterilisasi dengan autoklaf pada 121°C selama 15 menit. Kemudian siapkan wadah sesuai yang dibutuhkan. Nutrient broth merupakan media untuk mikroorganisme yang berbentuk cair. Intinya sama dengan nutrient agar. Nutrient broth dibuat dengan cara sebagai berikut.
1.      Larutkan 5 g pepton dalam 850 ml air distilasi/akuades.
2.      Larutkan 3 g ekstrak daging dalam larutan yang dibuat pada langkah pertama.
3.      Atur pH sampai 7,0.
4.      Beri air distilasi sebanyak 1.000 ml.
5.      Sterilisasi dengan autoklaf.

Nutrient  Agar (NA) merupakan suatu medium yang berbentuk padat, yang merupakan perpaduan antara bahan alamiah dan senyawa-senyawa kimia. NA dibuat dari campuran ekstrak daging dan peptone dengan menggunakan agar sebagai pemadat. Dalam hal ini agar digunakan sebagai pemadat, karena sifatnya yang mudah membeku dan mengandung karbohidrat yang berupa galaktam sehingga tidak mudah diuraikan oleh mikroorganisme. Dalam hal ini ekstrak beef dan pepton digunakan sebagai bahan dasar karena merupakan sumber protein, nitrogen, vitamin serta karbohidrat yang sangat dibutuhkan oleh mikroorganisme untuk tumbuh dan berkembang. Medium Nutrient Agar (NA) merupakan medium yang berwarna coklat muda yang memiliki konsistensi yang padat dimana medium ini berasal dari sintetik dan memiliki kegunaan sebagai medium untuk menumbuhkan bakteri.
Nutrient Broth (NB) adalah medium yang berbentuk cair dengan bahan dasar adalah ekstrak beef dan peptone. Perbedaan konsentris antara Nutrient Agar dengan Nutrient Broth yaitu nutrient agar berbentuk padat dan Nutrient Broth berbentuk cair. Susunan kimia sama-sama sintetik. Fungsi kimia dari nutrient agar dan nutrient broth sebagai medium umum. Medium Nutrient Broth (NB) merupakan medium yang berwarna coklat yang memiliki konsistensi yang cair dimana medium ini berasal dari sintetik dan memiliki kegunaan sebagai medium untuk menumbuhkan bakteri sama seperti medium NA.

Jual Bibit Nata De Coco (Acetobacter xylinum)

Acetobacter xylinum is a gram negative bacterium and is unique in its prolific synthesis of cellulose. Rows of pores characteristically secrete mini-crystals of glucan chains which then coalesce into microfibrils. Clusters of microfibrils result in a compound structure known as the ribbon. The ribbon can be observed directly using light microscopy, and the time lapse studies show Acetobacter cells generating cellulose. Acetobacter is the model system for study of the enzymes and genes involved in cellulose biosynthesis. The organism also promises to be an important future source for cellulose in the textile, paper, and lumber industries, provided its fermentation can be effectively scaled up.

Saccharomyces cerevisiae

Jual Culture Saccharomyces cerevisiae
Telp. 087731375234

Saccharomyces cerevisiae is a species of yeast. It has been instrumental to winemaking, baking, and brewing since ancient times. It is believed to have been originally isolated from the skin of grapes (one can see the yeast as a component of the thin white film on the skins of some dark-colored fruits such as plums; it exists among the waxes of the cuticle). It is one of the most intensively studied eukaryotic model organisms in molecular and cell biology, much like Escherichia coli as the model bacterium. It is the microorganism behind the most common type of fermentation. S. cerevisiae cells are round to ovoid, 5–10 μm in diameter. It reproduces by a division process known as budding.
Many proteins important in human biology were first discovered by studying their homologs in yeast; these proteins include cell cycle proteins, signaling proteins, and protein-processing enzymes. S. cerevisiae is currently the only yeast cell known to have Berkeley bodies present, which are involved in particular secretory pathways. Antibodies against S. cerevisiae are found in 60–70% of patients with Crohn's disease and 10–15% of patients with ulcerative colitis (and 8% of healthy controls).
"Saccharomyces" derives from Latinized Greek and means "sugar-mold" or "sugar-fungus", saccharo (σάκχαρις) being the combining form "sugar" and myces (μύκης, genitive μύκητος) being "fungus". Cerevisiae comes from Latin and means "of beer". Other names for the organism are:
In the 19th century, bread bakers obtained their yeast from beer brewers, and this led to sweet-fermented breads such as the Imperial "Kaisersemmel" roll,[4] which in general lacked the sourness created by the acidification typical of Lactobacillus. However, beer brewers slowly switched from top-fermenting (S. cerevisiae) to bottom-fermenting (S. pastorianus) yeast and this created a shortage of yeast for making bread, so the Vienna Process was developed in 1846.[5] While the innovation is often popularly credited for using steam in baking ovens, leading to a different crust characteristic, it is notable for including procedures for high milling of grains (see Vienna grits[6]), cracking them incrementally instead of mashing them with one pass; as well as better processes for growing and harvesting top-fermenting yeasts, known as press-yeast.
Refinements in microbiology following the work of Louis Pasteur led to more advanced methods of culturing pure strains. In 1879, Great Britain introduced specialized growing vats for the production of S. cerevisiae, and in the United States around the turn of the century centrifuges were used for concentrating the yeast,[7] making modern commercial yeast possible, and turning yeast production into a major industrial endeavor. The slurry yeast made by small bakers and grocery shops became cream yeast, a suspension of live yeast cells in growth medium, and then compressed yeast, the fresh cake yeast that became the standard leaven for bread bakers in much of the Westernized world during the early 20th century.
During World War II, Fleischmann's developed a granulated active dry yeast for the United States armed forces, which did not require refrigeration and had a longer shelf-life and better temperature tolerance than fresh yeast; it is still the standard yeast for US military recipes. The company created yeast that would rise twice as fast, cutting down on baking time. Lesaffre would later create instant yeast in the 1970s, which has gained considerable use and market share at the expense of both fresh and dry yeast in their various applications.
In nature, yeast cells are found primarily on ripe fruits such as grapes (before maturation, grapes are almost free of yeasts).[8] Since S. cerevisiae is not airborne, it requires a vector to move.Queens of social wasps overwintering as adults (Vespa crabro and Polistes spp.) can harbor yeast cells from autumn to spring and transmit them to their progeny.[9] The intestine of Polistesdominula, a social wasp, hosts S. cerevisiae strains as well as S. cerevisiae × S. paradoxus hybrids. Stefanini et al. (2016) showed that the intestine of Polistesdominulafavors the mating of S. cerevisiae strains, both among themselves and with S. paradoxus cells by providing environmental conditions prompting cell sporulation and spores germination.
The optimum temperature for growth of S. cerevisiae is 30–35 °C. Two forms of yeast cells can survive and grow: haploid and diploid. The haploid cells undergo a simple lifecycle of mitosis and growth, and under conditions of high stress will, in general, die. This is the asexual form of the fungus. The diploid cells (the preferential 'form' of yeast) similarly undergo a simple lifecycle of mitosis and growth. The rate at which the mitotic cell cycle progresses often differs substantially between haploid and diploid cells.[11] Under conditions of stress, diploid cells can undergo sporulation, entering meiosis and producing four haploid spores, which can subsequently mate. This is the sexual form of the fungus. Under optimal conditions, yeast cells can double their population every 100 minutes.[12][13] However, growth rates vary enormously both between strains and between environments.[14] Mean replicative lifespan is about 26 cell divisions.
In the wild, recessive deleterious mutations accumulate during long periods of asexual reproduction of diploids, and are purged during selfing: this purging has been termed "genome renewal". All strains of S. cerevisiae can grow aerobically on glucose, maltose, and trehalose and fail to grow on lactose and cellobiose. However, growth on other sugars is variable. Galactose and fructose are shown to be two of the best fermenting sugars. The ability of yeasts to use different sugars can differ depending on whether they are grown aerobically or anaerobically. Some strains cannot grow anaerobically on sucrose and trehalose.
All strains can use ammonia and urea as the sole nitrogen source, but cannot use nitrate, since they lack the ability to reduce them to ammonium ions. They can also use most amino acids, small peptides, and nitrogen bases as nitrogen sources. Histidine, glycine, cystine, and lysine are, however, not readily used. S. cerevisiae does not excrete proteases, so extracellular protein cannot be metabolized.
Yeasts also have a requirement for phosphorus, which is assimilated as a dihydrogen phosphate ion, and sulfur, which can be assimilated as a sulfate ion or as organic sulfur compounds such as the amino acids methionine and cysteine. Some metals, like magnesium, iron, calcium, and zinc, are also required for good growth of the yeast. Concerning organic requirements, most strains of S. cerevisiae require biotin. Indeed, a S. cerevisiae-based growth assay laid the foundation for the isolation, crystallisation, and later structural determination of biotin. Most strains also require pantothenate for full growth. In general, S. cerevisiae is prototrophic for vitamins.
Yeast has two mating types, a and α (alpha), which show primitive aspects of sex differentiation. As in many other eukaryotes, mating leads to genetic recombination, i.e. production of novel combinations of chromosomes. Two haploid yeast cells of opposite mating type can mate to form diploid cells that can either sporulate to form another generation of haploid cells or continue to exist as diploid cells. Mating has been exploited by biologists as a tool to combine genes, plasmids, or proteins at will.
The mating pathway employs a G protein-coupled receptor, G protein, RGS protein, and three-tiered MAPK signaling cascade that is homologous to those found in humans. This feature has been exploited by biologists to investigate basic mechanisms of signal transduction and desensitization. Growth in yeast is synchronised with the growth of the bud, which reaches the size of the mature cell by the time it separates from the parent cell. In well nourished, rapidly growing yeast cultures, all the cells can be seen to have buds, since bud formation occupies the whole cell cycle. Both mother and daughter cells can initiate bud formation before cell separation has occurred. In yeast cultures growing more slowly, cells lacking buds can be seen, and bud formation only occupies a part of the cell cycle.

Rhizopus oligosporus

Jual Culture Dan Starter Rhizopus oligosporus
Telp. 087731375234

Rhizopus oligosporus is a fungus of the family Mucoraceae and is a widely used starter culture for the production of tempeh at home and industrially. As the mold grows it produces fluffy, white mycelia, binding the beans together to create an edible "cake" of partly catabolized soybeans. The domestication of the microbe is thought to have occurred in Indonesia several centuries ago.
R. oligosporus is the preferred starter culture for tempeh production for several reasons. It grows effectively at high temperatures (30-40 °C) which are typical of the Indonesian islands, it exhibits strong lipolytic and proteolytic activity that create desirable properties in tempeh and it produces metabolites that allows it to inhibit and thus outcompete other molds and gram-positive bacteria, including the potentially harmful Aspergillus flavus and Staphylococcus aureus.
R. oligosporus is at present considered to be a domesticated form of Rhizopus microsporus and its proper taxonomic position is thus Rhizopus microsporus var. oligosporus. R. microsporus produces several potentially toxic metabolites, rhizoxin and rhizonins A and B, but it appears the domestication and mutation of the R. oligosporus genome has led to the loss of genetic material responsible for toxin production.
Rhizopus oligosporus is a fungus that belongs to the class Zygomycetes, which is one of two classes in the phylum Zygomycota. Rhizopus oligosporus belongs to the Rhizopus microsporus group. This group is made of taxa with similar morphology that are associated with undesired metabolite production, pathogenesis and food fermentation. Although other varieties in Rhizopus microscopus may be harmful, Rhizopus oligosporus is not associated with production of potentially harmful metabolites. It is not found in nature and is frequently used by humans.Rhizopus oligosporus strains have a large (up to 43 mm) and irregular spores with the most variable sizes. This is, for instance, reflected as high values in the spore volume (96–223 mm3/spore).Rhizopus oligosporus has large, subglobose to globose spores, and high proportion irregular spores (>10 %). Rhizopus oligosporusalso has spores with nonparallel valleys and ridges, and plateaus that sometimes are granular.
Rhizopus oligosporous role in Tempeh fermentation. A popular Indonesian food, Tempeh, is created by fermenting soybeans in combination with Rhizopus oligosporus. In order to create tempeh, soybeans must first be soaked in water (usually overnight) at a temperature similar to the environment it is placed in. The soybean’s outer covering is then removed and the beans are partially cooked. Lactic acid bacteria, like Lactococcus and Lb. casei species, play a major role in the fermentation of tempeh. For the tempeh to ferment, there needs to be a suitable, pure inoculum. Also, spores with a tendency for fast germinability are needed, as well. In order for the tempeh to attain its characteristic compact ‘cake’ form after fermentation, the soybeans become compressed due to the mycelia of Rhizopus oligosporus.Rapidly growing mycelia helps speed up the growth of this fungus. Because mycelia are quite sensitive to dehydration and adverse temperatures, preserving tempeh for extended periods of time can be challenging.
When the soybeans are bound together by the white mycelium, the fungus releases enzymes that make this heavily protein-rich product more digestible for humans. Tempeh-like foods can also be created from cereal grains such as wheat and rice. Many times, a good inoculum for this new fermentation actually comes from tiny pieces of old tempeh that have already been fermented.
Tempeh has the potential to be used in many high-protein foods due to its mild flavor when fried in vegetable oil.Containing more than 40% protein, tempeh is often used as a meat-substitute. This product is used in soups or can simply be sliced and seasoned.
Even after it is consumed, Rhizopus oligosporous produces an antibiotic that limits gram-positive bacteria like Staphylococcus aureus (potentially harmful) and Bacillus subtilis (beneficial). Thus, people who eat tempeh tend to have fewer intestinal infections.Tempeh contains ergosterol (provitamin D2). Beneficial effects of tempeh include inhibiting tumor development, lowering cholesterol and decreasing diarrhea issues, iron-defficient anaemia, lipid oxidation and hypertension.This fungus can also treat waste and wastewater, produce industrial enzymes and ferment other substrates like other legumes and cereals.

Posting Lama ►


Formula Pembuatan Tepung Mocaf

Acetobacter xylinum

Acetobacter xylinum
Bibit Nata De Coco

Copyright © 2012. AGROTEKNO LAB - All Rights Reserved Template IdTester by Blog Bamz