{"id":602,"date":"2023-08-01T22:06:01","date_gmt":"2023-08-01T16:21:01","guid":{"rendered":"https:\/\/microbiologypractical.com\/?p=219"},"modified":"2023-08-01T22:06:03","modified_gmt":"2023-08-01T16:21:03","slug":"starch-hydrolysis-test-objectives-principle-procedure-and-results","status":"publish","type":"post","link":"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/","title":{"rendered":"Starch Hydrolysis Test: Principle, Procedure, Results, Uses"},"content":{"rendered":"\n<p>Starch is the reserved food material of most plants and is one of the abundant carbohydrates in nature. Starch is a polysaccharide made of two glucose polymers \u2013amylose and amylopectin. Being a large macromolecule, starch can\u2019t be used in its native state by microorganisms; hence it must be broken down into glucose before metabolism. Bacterial extracellular amylase enzyme can hydrolyze starch into maltose and glucose. However, not all bacteria are capable of producing amylase <a href=\"https:\/\/microbenotes.com\/enzymes-properties-classification-and-significance\/\" data-type=\"post\" data-id=\"1065\">enzymes<\/a>.<\/p>\n\n\n\n<p><strong>The starch hydrolysis test, also known as the amylase test, is a biochemical test that is used to determine the ability of bacteria (microorganisms) to produce amylase and utilize starch as a carbon source. <\/strong>It is commonly used to differentiate species of <em>Bacillus, Clostridium, Corynebacterium, Fusobacterium, Streptococcus, Enterococcus, <\/em>and<em> Pseudomonas<\/em> genus.<\/p>\n\n\n\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_65 counter-hierarchy ez-toc-counter ez-toc-custom ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title \" >Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #0a0a0a;color:#0a0a0a\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #0a0a0a;color:#0a0a0a\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#objectives-of-starch-hydrolysis-test\" title=\"Objectives of Starch Hydrolysis Test\">Objectives of Starch Hydrolysis Test<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#principle-of-starch-hydrolysis-test\" title=\"Principle of Starch Hydrolysis Test\">Principle of Starch Hydrolysis Test<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#requirement-for-starch-hydrolysis-test\" title=\"Requirement for Starch Hydrolysis Test\">Requirement for Starch Hydrolysis Test<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#1-culture-media\" title=\"1. Culture Media\">1. Culture Media<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#2-reagents\" title=\"2. Reagents\">2. Reagents<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#3-equipment\" title=\"3. Equipment\">3. Equipment<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#4-test-organism-sample-bacteria\" title=\"4. Test Organism (Sample Bacteria)\">4. Test Organism (Sample Bacteria)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#5-control-organisms\" title=\"5. Control Organisms\">5. Control Organisms<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#procedure-of-starch-hydrolysis-test\" title=\"Procedure of Starch Hydrolysis Test\">Procedure of Starch Hydrolysis Test<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#result-and-interpretation-of-starch-hydrolysis-test\" title=\"Result and Interpretation of Starch Hydrolysis Test\">Result and Interpretation of Starch Hydrolysis Test<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#starch-hydrolysis-test-results-of-some-common-bacterial-pathogens\" title=\"Starch Hydrolysis Test Results of Some Common Bacterial Pathogens\">Starch Hydrolysis Test Results of Some Common Bacterial Pathogens<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#quality-control\" title=\"Quality Control\">Quality Control<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#precautions\" title=\"Precautions\">Precautions<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#applications-of-starch-hydrolysis-test\" title=\"Applications of Starch Hydrolysis Test\">Applications of Starch Hydrolysis Test<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#limitations-of-starch-hydrolysis-test\" title=\"Limitations of Starch Hydrolysis Test\">Limitations of Starch Hydrolysis Test<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/#references\" title=\"References\">References<\/a><\/li><\/ul><\/nav><\/div>\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"objectives-of-starch-hydrolysis-test\"><\/span><strong>Objectives of Starch Hydrolysis Test<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul>\n<li>To determine the ability of bacteria to produce amylase enzyme<\/li>\n\n\n\n<li>To determine the ability of bacteria to hydrolyze starch<\/li>\n\n\n\n<li>To differentiate and identify bacteria based on their ability to hydrolyze starch<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"principle-of-starch-hydrolysis-test\"><\/span><strong>Principle of Starch Hydrolysis Test<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul>\n<li>Bacteria capable of producing extracellular amylase enzymes can hydrolyze the starch and produce smaller water-soluble sugar molecules like glucose, maltose, and dextrose. If the bacteria are not able to secret the amylase enzyme, there won\u2019t be hydrolysis of starch.&nbsp;<\/li>\n\n\n\n<li>If the inoculated bacteria produce amylase, the starch molecules around the colonies will be hydrolyzed and there won\u2019t be amylose or starch molecules. Hence, upon the addition of iodine solution, there won\u2019t be the formation of dark blue color around the colonies.&nbsp;<\/li>\n\n\n\n<li>If the inoculated bacteria produce amylase, starch molecules around the bacterial colony will be hydrolyzed; so there won\u2019t be color development in the medium surrounding the colony upon the addition of iodine solution.&nbsp;<\/li>\n\n\n\n<li>Thus, hydrolysis of starch can be identified by the formation of a clear zone of halo around the bacterial growth after the addition of iodine solution in the inoculated and incubated starch medium.&nbsp;<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"requirement-for-starch-hydrolysis-test\"><\/span><strong>Requirement for Starch Hydrolysis Test<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"1-culture-media\"><\/span><strong>1. Culture Media<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Mueller Hinton Agar (MHA), Starch Agar, and Heart Infusion Agar with 2% Starch are commonly used for the detection of starch hydrolysis.&nbsp;<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Composition of Mueller Hinton Agar per 1000 mL<\/strong><\/h4>\n\n\n\n<p>HM Infusion B form (Beef Infusion) 300.00 grams<\/p>\n\n\n\n<p>Acicase (Casein Acid Hydrolysate) 17.500 grams<\/p>\n\n\n\n<p>Starch 1.5000 grams<\/p>\n\n\n\n<p>Agar 17.000 grams<\/p>\n\n\n\n<p>Final pH 7.3 0.1 at 25<sup>0<\/sup>C<\/p>\n\n\n\n<p><em>Reference:<\/em> <a href=\"https:\/\/www.himedialabs.com\/media\/TD\/SM173.pdf\" target=\"_blank\" rel=\"noreferrer noopener nofollow\">SM173.pdf (himedialabs.com)<\/a>\u00a0<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Preparation of MH Agar<\/strong><\/h4>\n\n\n\n<ul>\n<li>Measure the appropriate amount of MHA media powder (38.0 grams per 1000 mL) and dissolve it in the water of the required volume in a conical flask (or glass bottle).&nbsp;<\/li>\n\n\n\n<li>Stir well in a magnetic stirrer or manually and heat to boil to completely dissolve the media powder.<\/li>\n\n\n\n<li>Autoclave the medium at 121\u00b0C and 15 lbs. pressure for 15 minutes.\u00a0<\/li>\n\n\n\n<li>When the medium is cooled to around 40 to 45\u00b0C, in a sterile petri dish (of 10 cm diameter) dispense about 20 to 25 mL of the medium and let it solidify.\u00a0<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Composition of Starch Agar per 1000 mL<\/strong><\/h4>\n\n\n\n<p>Meat Extract- 3.00 grams<\/p>\n\n\n\n<p>Peptic Digest of Animal Tissue- 5.00 grams<\/p>\n\n\n\n<p>Starch- 2.00 grams<\/p>\n\n\n\n<p>Agar- 15.0 grams<\/p>\n\n\n\n<p>Final pH- 7.2 0.1 at 25\u00b0C<\/p>\n\n\n\n<p><em>Reference: <\/em><a href=\"https:\/\/www.himedialabs.com\/media\/TD\/M107S.pdf\" target=\"_blank\" rel=\"noreferrer noopener nofollow\"><em>M107S.pdf (himedialabs.com)<\/em><\/a><em>\u00a0<\/em><\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Preparation of Starch Agar<\/strong><\/h4>\n\n\n\n<ul>\n<li>Measure the appropriate amount of Starch Agar media powder (25.0 grams per 1000 mL) and dissolve it in the water of the required volume in a conical flask (or glass bottle).&nbsp;<\/li>\n\n\n\n<li>Stir well in a magnetic stirrer or manually and heat to boil to completely dissolve the media powder.<\/li>\n\n\n\n<li>Autoclave the medium at 121\u00b0C and 15 lbs. pressure for 15 minutes.\u00a0<\/li>\n\n\n\n<li>When the medium is cooled to around 40 to 45\u00b0C, in a sterile petri dish (of 10 cm diameter) dispense about 20 to 25 mL of the medium and let it solidify.\u00a0<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"2-reagents\"><\/span><strong>2. Reagents<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><strong>Gram\u2019s Iodine Solution<\/strong> is required for the detection of starch hydrolysis.&nbsp;<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Preparation of Gram\u2019s Iodine Solution:<\/strong><\/h4>\n\n\n\n<ul>\n<li>Dissolve 25 grams of Iodine Crystal and 50 grams of potassium iodide in 500 mL of distilled water to make Lugol\u2019s iodine stock solution.&nbsp;<\/li>\n\n\n\n<li>Dissolve 5 grams of sodium bicarbonate (NaHCO<sub>3<\/sub>) in 100 mL of distilled water to make 5% sodium bicarbonate solution.<\/li>\n\n\n\n<li>Mix 60 mL of Lugol\u2019s iodine solution and 60 mL of 5% sodium bicarbonate solution with 220 mL of distilled water to make Gram\u2019s Iodine Solution.&nbsp;<\/li>\n<\/ul>\n\n\n\n<p><em>(Reference: Leber, Amy L., editor in chief. (2016). Clinical microbiology procedures handbook (Fourth <\/em><em>edition). Washington, DC: ASM Press 1752 N St., N.W., [2016]<\/em><em> doi:10.1128\/9781555818814.ch3.17.33. Appendix 3.2.1-1; Preparation of Gram Stain Reagents)&nbsp;<\/em><\/p>\n\n\n\n<p><strong>Alternatively:<\/strong><\/p>\n\n\n\n<ul>\n<li>Dissolve 1.0 grams of iodine and 2.0 mL gram of potassium iodide in 300 mL of distilled water.<\/li>\n<\/ul>\n\n\n\n<p><em>(Reference:\u00a0<\/em><a href=\"https:\/\/www.himedialabs.com\/media\/TD\/S013.pdf\" target=\"_blank\" rel=\"noreferrer noopener nofollow\"><em>S013.pdf (himedialabs.com)<\/em><\/a><em>)<\/em><\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3-equipment\"><\/span><strong>3. Equipment<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><a href=\"https:\/\/microbenotes.com\/petri-dish-plate\/\" data-type=\"post\" data-id=\"40633\">Petri Plate<\/a><br><a href=\"https:\/\/microbenotes.com\/incubator\/\" data-type=\"post\" data-id=\"28326\">Incubator<\/a><\/td><td>Dropper<br><a href=\"https:\/\/microbenotes.com\/autoclave\/\" data-type=\"post\" data-id=\"28626\">Autoclave<\/a><\/td><td><a href=\"https:\/\/microbenotes.com\/bunsen-burner-principle-parts-types-procedure-uses\/\" data-type=\"post\" data-id=\"39300\">Bunsen burner<\/a><br>Weighing Machine<\/td><td><a href=\"https:\/\/microbenotes.com\/inoculating-loops-needles-principle-parts-types-uses\/\" data-type=\"post\" data-id=\"39810\">Inoculating loop<\/a><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"4-test-organism-sample-bacteria\"><\/span><strong>4. Test Organism (Sample Bacteria)<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"5-control-organisms\"><\/span><strong>5. Control Organisms<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p><em>Bacillus cereus<\/em> ATCC \u2013 10876&nbsp;<\/p>\n\n\n\n<p><em>Escherichia coli <\/em>ATCC \u2013 25922<\/p>\n\n\n\n<p><em>Streptococcus bovis<\/em> ATCC \u2013 33317<\/p>\n\n\n\n<p><em>Staphylococcus aureus<\/em> ATCC \u2013 25923&nbsp;<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"procedure-of-starch-hydrolysis-test\"><\/span><strong>Procedure of Starch Hydrolysis Test<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul>\n<li>Using a sterile inoculating loop (or cotton swab) pick up the sample bacteria from several fresh colonies (of about 18 to 20 hours).<\/li>\n\n\n\n<li>Streak the bacteria in the form of short and thick straight lines over the surface of the bacteria. (Multiple bacteria can be tested in a single plate forming multiple lines.)<\/li>\n\n\n\n<li>Incubate at 35\u00b12\u00b0C for at least 48 hours.\u00a0<\/li>\n\n\n\n<li>Following incubation, add a few drops of iodine solution directly over the colonies and observe for the formation of a clear halo around the colonies.&nbsp;<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"result-and-interpretation-of-starch-hydrolysis-test\"><\/span><strong>Result and Interpretation of Starch Hydrolysis Test<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul>\n<li><strong>A positive result<\/strong> is indicated by the formation of a clear halo around the colonies and the development of dark blue to purple-blue color in the surrounding medium after the addition of Gram\u2019s Iodine.&nbsp;<\/li>\n\n\n\n<li><strong>A negative result<\/strong> is indicated by no clear halo around the colonies and the development of dark blue to purple-blue color in the surrounding medium after the addition of Gram\u2019s Iodine.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1205\" height=\"631\" src=\"https:\/\/microbenotes.com\/wp-content\/uploads\/2023\/08\/Starch-Hydrolysis-Test.jpg\" alt=\"Starch Hydrolysis Test\" class=\"wp-image-40737\" srcset=\"https:\/\/microbenotes.com\/wp-content\/uploads\/2023\/08\/Starch-Hydrolysis-Test.jpg 1205w, https:\/\/microbenotes.com\/wp-content\/uploads\/2023\/08\/Starch-Hydrolysis-Test-300x157.jpg 300w, https:\/\/microbenotes.com\/wp-content\/uploads\/2023\/08\/Starch-Hydrolysis-Test-1024x536.jpg 1024w, https:\/\/microbenotes.com\/wp-content\/uploads\/2023\/08\/Starch-Hydrolysis-Test-768x402.jpg 768w\" sizes=\"(max-width: 1205px) 100vw, 1205px\" \/><figcaption class=\"wp-element-caption\"><strong>Starch Hydrolysis Test<\/strong><\/figcaption><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"starch-hydrolysis-test-results-of-some-common-bacterial-pathogens\"><\/span><strong>Starch Hydrolysis Test Results of Some Common Bacterial Pathogens<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<ul>\n<li>Starch hydrolyzing (amylase producing) bacteria: <em>S. bovis, Bacillus subtilis, B. cereus, B. megaterium, Clostridium perfringens,<\/em> etc.<\/li>\n\n\n\n<li>Starch non-hydrolyzing (amylase non-producing) bacteria:&nbsp; <em>Corynebacterium diphtheria, Clostridium difficile, C. botulinum<\/em>, bile-esculin positive viridans <em>Streptococci<\/em> except <em>S. bovis, E. coli, S. aureus, Pseudomonas aeruginosa, P. putida<\/em>, etc.&nbsp;<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"quality-control\"><\/span><strong>Quality Control<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul>\n<li><em>Bacillus cereus<\/em> ATCC \u2013 10876 and <em>Streptococcus bovis<\/em> ATCC \u2013 33317 gives positive result i.e. formation of a clear halo around their colonies is observed after the addition of the Gram\u2019s iodine while the rest of the medium turns dark blue colored.&nbsp;<\/li>\n\n\n\n<li><em>E. coli<\/em> ATCC \u2013 25922 and <em>Staphylococcus aureus<\/em> ATCC \u2013 25923 gives negative result i.e. don\u2019t form a clear halo around their colonies but the surrounding medium turns dark blue after the addition of the Gram\u2019s iodine solution.&nbsp;<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"precautions\"><\/span><strong>Precautions<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul>\n<li>Add Gram\u2019s iodine only after 48 hours of incubation. Testing earlier may give a false negative result.&nbsp;<\/li>\n\n\n\n<li>While using multiple specimens in a single plate, make sure to streak colonies apart from each other making a gap of about 25 mm or more.&nbsp;<\/li>\n\n\n\n<li>Don\u2019t use a medium containing a high amount of glucose because bacteria may use glucose instead of starch and give false negative results.&nbsp;<\/li>\n\n\n\n<li>Read the result quickly after the addition of iodine solution because the blue color may fade as time passes.&nbsp;<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"applications-of-starch-hydrolysis-test\"><\/span><strong>Applications of Starch Hydrolysis Test<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul>\n<li>To differentiate species of <em>Bacillus, Clostridium, Corynebacterium, Fusobacterium, Streptococcus, Enterococcus, <\/em>and<em> Pseudomonas<\/em> genus.<\/li>\n\n\n\n<li>To separate <em>S. bovis <\/em>from other Bile-esculin positive viridans <em>Streptococci<\/em>.&nbsp;<\/li>\n\n\n\n<li>To separate <em>Chryseobacetrium indologenes<\/em> from <em>Elizabethkinga meningoseptica<\/em>; earlier positive while later negative.&nbsp;&nbsp;<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"limitations-of-starch-hydrolysis-test\"><\/span><strong>Limitations of Starch Hydrolysis Test<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul>\n<li>It is not a confirmatory test and hence requires other biochemical test results to completely identify isolated bacteria.<\/li>\n\n\n\n<li>It requires a longer time period (at least 48 hours).&nbsp;<\/li>\n\n\n\n<li>Once Gram\u2019s iodine is added over the medium, bacteria can\u2019t be used for further culture or other tests from the plate.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"references\"><\/span><strong>References<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ol>\n<li>Leber, Amy L., editor in chief. (2016). Clinical microbiology procedures handbook (Fourth edition) . Washington, DC : ASM Press 1752 N St., N.W., [2016] doi:10.1128\/9781555818814.ch3.17.33<\/li>\n\n\n\n<li>Tille, P. M., &amp; Forbes, B. A. (2014). Bailey &amp; Scott\u2019s diagnostic microbiology (Thirteenth edition.) P. 185 &#8211; 187. St. Louis, Missouri: Elsevier<\/li>\n\n\n\n<li>https:\/\/microbiologyinfo.com\/starch-hydrolysis-test\/<\/li>\n\n\n\n<li><a href=\"https:\/\/www.uwyo.edu\/molb2021\/additional_info\/summ_biochem\/starch.html\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/www.uwyo.edu\/molb2021\/additional_info\/summ_biochem\/starch.html<\/a><\/li>\n\n\n\n<li>https:\/\/microbeonline.com\/starch-hydrolysis-test\/<\/li>\n\n\n\n<li>https:\/\/bio.libretexts.org\/Bookshelves\/Microbiology\/Microbiology_Laboratory_Manual_(Hartline)\/01%3A_Labs\/1.17%3A_Starch_Hydrolysis<\/li>\n\n\n\n<li>https:\/\/microbiologynote.com\/starch-hydrolysis-test\/<\/li>\n\n\n\n<li>https:\/\/www.narajolerajcollege.ac.in\/document\/sub_page\/20210610_233752.pdf<\/li>\n\n\n\n<li>https:\/\/asm.org\/ASM\/media\/Protocol-Images\/Starch-Agar-Protocol.pdf?ext=.pdf<\/li>\n\n\n\n<li>https:\/\/www.deshbandhucollege.ac.in\/pdf\/resources\/1586748276_BT(H)-VI-IEM-Hydrolysis_of_starch_by_microorganisms.pdf<\/li>\n\n\n\n<li>https:\/\/www.sas.upenn.edu\/LabManuals\/biol275\/Table_of_Contents_files\/21-DiagnosticTests.pdf<\/li>\n\n\n\n<li>S013.pdf (himedialabs.com))<\/li>\n\n\n\n<li>M107S.pdf (himedialabs.com)<\/li>\n\n\n\n<li>SM173.pdf (himedialabs.com)<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>Starch is the reserved food material of most plants and is one of the abundant carbohydrates in nature. Starch is a polysaccharide made of two glucose polymers \u2013amylose and amylopectin. &#8230; <a title=\"Starch Hydrolysis Test: Principle, Procedure, Results, Uses\" class=\"read-more\" href=\"https:\/\/microbenotes.com\/starch-hydrolysis-test-objectives-principle-procedure-and-results\/\" aria-label=\"Read more about Starch Hydrolysis Test: Principle, Procedure, Results, Uses\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":40737,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[998,999,1000,1001,1002,1003,1004],"custom":{"td_video":"","featured_image":"https:\/\/microbenotes.com\/wp-content\/uploads\/2023\/08\/Starch-Hydrolysis-Test.jpg","author":{"name":"Sagar Aryal","avatar":"https:\/\/secure.gravatar.com\/avatar\/862472ea06500d4318f1ad82addb608e?s=96&d=mm&r=g"},"categories":[{"term_id":702,"name":"Biochemical Test","slug":"biochemical-test","term_group":0,"term_taxonomy_id":702,"taxonomy":"category","description":"<strong>Biochemical tests are the tests that are performed on different bacteria for their identification on the basis of their biochemical activities towards different biochemical compounds.<\/strong>\r\n<ul>\r\n \t<li>Biochemical tests are one of the traditional methods for the identification of microorganisms, usually performed with phenotypic identification.<\/li>\r\n \t<li>For many years these methods were employed extensively, and they continue to be used nowadays, especially in some laboratory routines where a particular type of microorganism has to be identified rapidly.<\/li>\r\n \t<li>The ability of microorganisms to utilize certain biomolecules, resulting in useful organic compounds for themselves forms the basis of various biochemical tests.<\/li>\r\n \t<li>Biochemical tests are of different types, where the identification or distinction between different microorganisms is made on various bases.<\/li>\r\n \t<li>One of the traditional methods commonly used is a simple visual detection of the growth of the organism in the presence of essential nutrients by increased turbidity in the liquid medium.<\/li>\r\n \t<li>In other tests, however, the results are based on the change in color of the medium as a result of the change in the pH of the medium.<\/li>\r\n \t<li>Microorganisms can be classified into different groups on the basis of their reaction to such tests. Some tests even allow the distinction of microorganisms to the species level.<\/li>\r\n \t<li>Biochemical tests are thus, essential as they are inexpensive and relatively simple to perform.<\/li>\r\n \t<li>The physiology of bacteria and other microorganisms differs from one another, which allows for the differentiation of such microorganisms.<\/li>\r\n \t<li>Biochemical tests, however, have some disadvantages. Despite being inexpensive and allowing both quantitative and qualitative information about the diversity of microorganisms present in a sample, these methods are laborious and time-consuming, and results are only observed after several days.<\/li>\r\n \t<li>In some cases, false positives are obtained, especially when considering similar microbial species.<\/li>\r\n<\/ul>","parent":0,"count":114,"filter":"raw","cat_ID":702,"category_count":114,"category_description":"<strong>Biochemical tests are the tests that are performed on different bacteria for their identification on the basis of their biochemical activities towards different biochemical compounds.<\/strong>\r\n<ul>\r\n \t<li>Biochemical tests are one of the traditional methods for the identification of microorganisms, usually performed with phenotypic identification.<\/li>\r\n \t<li>For many years these methods were employed extensively, and they continue to be used nowadays, especially in some laboratory routines where a particular type of microorganism has to be identified rapidly.<\/li>\r\n \t<li>The ability of microorganisms to utilize certain biomolecules, resulting in useful organic compounds for themselves forms the basis of various biochemical tests.<\/li>\r\n \t<li>Biochemical tests are of different types, where the identification or distinction between different microorganisms is made on various bases.<\/li>\r\n \t<li>One of the traditional methods commonly used is a simple visual detection of the growth of the organism in the presence of essential nutrients by increased turbidity in the liquid medium.<\/li>\r\n \t<li>In other tests, however, the results are based on the change in color of the medium as a result of the change in the pH of the medium.<\/li>\r\n \t<li>Microorganisms can be classified into different groups on the basis of their reaction to such tests. Some tests even allow the distinction of microorganisms to the species level.<\/li>\r\n \t<li>Biochemical tests are thus, essential as they are inexpensive and relatively simple to perform.<\/li>\r\n \t<li>The physiology of bacteria and other microorganisms differs from one another, which allows for the differentiation of such microorganisms.<\/li>\r\n \t<li>Biochemical tests, however, have some disadvantages. Despite being inexpensive and allowing both quantitative and qualitative information about the diversity of microorganisms present in a sample, these methods are laborious and time-consuming, and results are only observed after several days.<\/li>\r\n \t<li>In some cases, false positives are obtained, especially when considering similar microbial species.<\/li>\r\n<\/ul>","cat_name":"Biochemical Test","category_nicename":"biochemical-test","category_parent":0}]},"_links":{"self":[{"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/posts\/602"}],"collection":[{"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/comments?post=602"}],"version-history":[{"count":0,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/posts\/602\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/media\/40737"}],"wp:attachment":[{"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/media?parent=602"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/categories?post=602"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/tags?post=602"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}