==Metabolism==
All metabolism by Lactobacillus, including growth, will require sugar to be consumed and lactate (lactic acid) to be produced. Two categories of metabolism exist, :''Editor'homolactic''' and '''heterolactic'''. ''Homolactic'' metabolism is described as s note: the cell catabolizing one molecule of glucose to yield two molecules of pyruvatefollowing section was reviewed for accuracy by MTF members Bryan Heit, which is then further reduced to two molecules of lactate (lactic acid). ''Heterolactic'' metabolism is described as the cell catabolizing one molecule of glucose into one molecule of CO2Matt Humbard, one molecule of glyceraldehyde phosphateLance Shaner, and one molecule of acetyl phosphateRichard Preiss. The molecule ''===Types of glyceraldehyde phosphate is reduced to one molecule of lactate, and the acetyl phosphate is reduced to one molecule of ethanol (or one molecule of acetic acid instead of ethanol, depending on its growing environment <ref nameMetabolism==="Raunak">[[httpsFile://raunakmsHomolactic heterolactic.wordpressJPG|thumb|upright=2.com/2011/01/30/lactic-acid-bacteria/ Lactic Acid Bacteria. Raunak Shrestha. Retrieved 6/7/2015.]</ref>). ''5|Homolactic'' fermentation only allows the fermentation of hexoses (glucose), while ''heterolactic'' fermentation allows the fermentation of hexoses and pentoses Heterolactic pathways <refname="Effects on Food Properties">[https://books.google.com/books?id=eZjIfud742wC6SLB1j0rX78C&pg=PA33PA76&lpg=PA33PA76&dq=facultativewhat+is+obligatory+facultatively+heterofermentative&source=bl&ots=QQYpzpsrvC6E4DB8Px_X&sig=kkyP7wUjgWiE2UV2qkIaRyxMMGAPXZTNO4fB3ifCF_qAl5_I4euKmk&hl=en&sa=X&ei=K_d0VYDJPLX9sATv_IXgAQZ-10VZqvFIWyggTInIHYBw&ved=0CDIQ6AEwBDgK0CCsQ6AEwAw#v=onepage&q=facultativewhat%20is%20obligatory%20facultatively%20heterofermentative&f=false Handbook of Dough FermentationsFermentation: Effects on Food Properties. Karel KulpBhavbhuti M. Mehta, Afaf Kamal-Eldin, Klaus LorenzRobert Z. Iwanski. CRC Press, May 20Apr 12, 20032012. Pg 3376,77.]</ref>. In summary, ''homolactic'' fermentation produces only lactic acid, while ''heterolactic'' fermentation produce lactic acid, CO2, and ethanol/acetic acid <ref>[http://textbookofbacteriology.net/lactics_2.html Todar's Online Texbook of Bacteriology. Kenneth Todar, PhD. Retrieved 05/06/2015.]</ref>.]
There are three All metabolism by Lactobacillus, including growth, will require sugar to be consumed and lactate (lactic acid) to be produced. Two categories of ''Lactobacillus'' based on the type of fermentation they are capable of (metabolism exist, ''homolactic'', and ''heterolactic''. In summary, or both): '''obligatory homofermentative'homolactic''fermentation produces only lactic acid, while '''obligatory heterofermentative'heterolactic''fermentation produce lactic acid, CO2, and ethanol/acetic acid <ref>[http://textbookofbacteriology.net/lactics_2.html Todar's Online Texbook of Bacteriology. Kenneth Todar, PhD. Retrieved 05/06/2015.]</ref>. ====Homolactic====''facultatively heterofermentative'Homolactic''metabolism is described as the cell catabolizing one molecule of glucose to yield two molecules of pyruvate, which is then further reduced to two molecules of lactate (lactic acid). ''Obligatory homofermentativeHomolactic'' bacteria fermentation only perform allows the fermentation of hexoses (glucose). ''homolacticHomolactic'' fermentation, and thus only produce lactic acid. metabolism follows the ''Obligatory heterofermentativeEmbden-Meyerhof-Parnas'' bacteria only perform pathway <ref name="Effects on Food Properties"></ref>. ====Heterolactic==== ''heterolacticHeterolactic'' fermentationmetabolism is described as the cell catabolizing one molecule of glucose into one molecule of CO2, one molecule of glyceraldehyde phosphate, and thus produce lactic acid, CO2one molecule of acetyl phosphate. The molecule of glyceraldehyde phosphate is reduced to one molecule of lactate, and the acetyl phosphate is reduced to one molecule of ethanol (or sometimes one molecule of acetic acid instead of ethanol, depending on its growing environment <ref name="Raunak">[https://raunakms.wordpress.com/2011/01/30/lactic-acid-bacteria/ Lactic Acid Bacteria. Raunak Shrestha. Retrieved 6/7/2015.]</ref>). ''Facultatively heterofermentativeHeterolactic'' bacteria generally are ''homolactic'' when there is an abundance fermentation allows the fermentation of carbohydrates, but can also perform ''heterolactic'' fermentation when carbohydrates are not abundant hexoses and pentoses <ref>[https://books.google.com/books?id=6SLB1j0rX78CeZjIfud742wC&pg=PA76PA33&lpg=PA76PA33&dq=what+is+obligatory+facultativelyfacultative+heterofermentative&source=bl&ots=6E4DB8Px_XQQYpzpsrvC&sig=PXZTNO4fB3ifCF_qAl5_I4euKmkkkyP7wUjgWiE2UV2qkIaRyxMMGA&hl=en&sa=X&ei=Z-10VZqvFIWyggTInIHYBwK_d0VYDJPLX9sATv_IXgAQ&ved=0CCsQ6AEwAw0CDIQ6AEwBDgK#v=onepage&q=what%20is%20obligatory%20facultativelyfacultative%20heterofermentative&f=false Fermentation: Handbook of Dough Fermentations. Karel Kulp, Klaus Lorenz. CRC Press, May 20, 2003. Pg 33.]</ref>. ''Heterolactic'' fermentation follows the ''pentose phosphate'' pathway, or also called the ''phosphogluconate'' pathway <ref name="Effects on Food Properties"></ref>. Bhavbhuti M. Mehta ===Categories of Lactobacillus===There are three categories of ''Lactobacillus'' based on the type of fermentation they are capable of (''homolactic'', Afaf Kamal-Eldin''heterolactic'', Robert Zor both). Iwanski # '''Obligatory homofermentative''' Lactobacillus only perform ''homolactic'' fermentation, and thus only produce lactic acid <ref name="Effects on Food Properties"></ref>. CRC Press# '''Obligatory heterofermentative''' Lactobacillus only perform ''heterolactic'' fermentation, and thus produce lactic acid, Apr 12CO2, 2012and ethanol (or sometimes acetic acid instead of ethanol) <ref name="Effects on Food Properties"></ref>. Pg 76.]# '''Facultatively heterofermentative''' Lactobacillus generally are ''homolactic'' when there is an abundance of carbohydrates, but can also perform ''heterolactic'' fermentation when carbohydrates are not abundant <ref name="Effects on Food Properties"></ref>.
Other factors can determine if a ''facultative heterofermentative'' species uses ''homolactic'' or ''heterolactic'' fermentation. For example, L. plantarum, which is a ''facultative heterofermentative'' species, is ''homolactic'' without the presence of oxygen. In the presence of oxygen, however, it performs ''heterolactic'' fermentation, and produces acetic acid <ref>[https://microbewiki.kenyon.edu/index.php/Lactobacillus_plantarum_and_its_biological_implications Lactobacillus plantarum and its biological implications. Microbe Wiki. Retrieved 6/7/2015.]</ref><ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1083842231643990/?comment_id=1084922688202611&offset=0&total_comments=28&comment_tracking=%7B%22tn%22%3A%22R%22%7D Conversation with Lance Shaner about L. plantarum on MTF. 6/7/2015.]</ref>.