Pengukuran Pertumbuhan Mikroba dengan Menghitung · PDF fileTitle: Microsoft PowerPoint - pertumbuhan mikr07 [Compatibility Mode] Author: My Computer Created Date: 12/4/2007 12:01:28

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Pengukuran Pertumbuhan Mikroba dengan Menghitung Jumlah Mikroba

• Pertumbuhan Mikrobia = peningkatan jumlah/ massa sel, bukan peningkatan ukuran sel

Cara reproduksi pada prokariot:• Pembelahan sel• Tunas• Konidiospora (actinomycetes)

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• Fragmentasi filamen

Pembelahan sel

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Penambahan jumlah sel akibat pembelahan biner sel bakteri

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Jika 100 sel ditumbuhkan selama 5 jam dan menghasilkan 1.720.320 sel:

Contoh perhitungan

Jumlah generasi = (log 1.720.320 – log 100)/0,301 = 14

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Waktu generasi = (60 X 5)/14 = 21 menit/generasi

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Grafik pertumbuhan mikroba dalam satuan bilangan logaritma

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Kurva pertumbuhan mikroba dalam kultur tertutup (batch culture)

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Pengukuran langsung pertumbuhan mikrobia

• Plate Counts: Mendasarkan pada seri pengenceran sampel

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Plate Count

• Inokulasi cawan Petri dari seri pengenceran

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Plate Count• Setelah inkubasi, hitung koloni pada cawan yang

memiliki jumlah 25-250 koloni (CFU)

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Pengukuran tidak langsung pertumbuhan mikrobia

• Tabung ganda (uji MPN)

• Hitung tabung positif dan bandingkan dengan tabel MPN.

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Pengukuran tidak langsung pertumbuhan mikrobia

• Filtrasi

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Pendugaan Jumlah Bakteri dengan Metode Tidak Langsung

• Turbiditas

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Pengukuran langsung pertumbuhan mikrobia

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Pengukuran langsung pertumbuhan mikrobia• Hitung langsung dengan Mikroskop

Pendugaan jumlah sel dengan pengukuran

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tidak langsung:-Pengukuran aktivitas metabolik (misal: pengukuran CO2)

-Pengukuran berat kering sel

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Pertumbuhan Mikroba

Kebutuhan fisik pertumbuhan:1. Suhu pertumbuhan:

Suhu minimum, optimum, maksimum 2. pH medium:

Kebanyakan bakteri tumbuh antara pH 6.5 and 7.5Jamur dan khamir tumbuh antara pH 5 and 6

Acidofil tumbuh dalam lingkungan asam3. Tekanan Osmotik

Li k Hi ik i k l

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Lingkungan Hipertonik, peningkatan garam atau gula, menyebabkan plasmolisis

Halofil Ekstrim atau obligat membutuhkan tekanan osmotik tinggi

Halofil fakultatif toleran thd tekanan osmotik tinggi

Suhu Pertumbuhan

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Pembagian mikroba menurut suhu pertumbuhan

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Lingkungan pertumbuhan

• Sumber karbon: ototrof (C-CO2) dan heterotrof (C-organik)• Sumber energi: fototrof (energi matahari) dan khemotrof (reaksi kimia)• Donor elektron: litotrof (senyawa anorganik) dan organotrof (organik)

Kebutuhan Oksigen (O ):• Kebutuhan Oksigen (O2):

obligate aerobes

Faultative anaerobes

Obligate anaerobes

Aerotolerant anaerobes Microaerophiles

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Selamat belajar

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