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Micrococcus
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<p><i>Micrococcus</i> is a <a href="/facts/Genus/m8EFjSms">genus</a> of <a href="/facts/Bacteria/wC8xSCsU">bacteria</a> in the <a href="/facts/Micrococcaceae/LNaxjjdL">Micrococcaceae</a> <a href="/facts/Family_(biology)/qTrn6E8E">family</a>. <i>Micrococcus</i> occurs in a wide range of environments, including water, dust, and soil. Micrococci have <a href="/facts/Gram-positive/H6WYQ17e">Gram-positive</a> spherical cells ranging from about 0.5 to 3 micrometers in diameter and typically appear in tetrads. They are <a href="/facts/Catalase/CcJ9r5KG">catalase</a> positive, <a href="/facts/Oxidase/MWIPq1cQ">oxidase</a> positive, <a href="/facts/Indole/HT72P6e6">indole</a> negative and <a href="/facts/Citrate_test/MAqT7I4Y">citrate</a> negative. <i>Micrococcus</i> has a substantial <a href="/facts/Cell_wall/DYXJVrnw">cell wall</a>, which may comprise as much as 50% of the cell mass. The genome of <i>Micrococcus</i> is rich in <a href="/facts/Guanine/hoTSpz0x">guanine</a> and <a href="/facts/Cytosine/JW20j33u">cytosine</a> (GC), typically exhibiting 65 to 75% <a href="/facts/GC-content/nRoVl7gw">GC-content</a>. Micrococci often carry <a href="/facts/Plasmid/yf59JVlA">plasmids</a> (ranging from 1 to 100 MDa in size) that provide the organism with useful traits. </p><p>Some species of <i>Micrococcus</i>, such as <i>M. luteus</i> (yellow) and <i>M. roseus</i> (red) produce yellow or pink colonies when grown on mannitol salt agar. Isolates of <i>M. luteus</i> have been found to overproduce <a href="/facts/Riboflavin/M8D8EbmD">riboflavin</a> when grown on toxic organic pollutants like pyridine. </p>