title: Analysis of hemin effect on lactate reduction in Lactococcus lactis.
abstract: Lactococcus lactis is a facultative anaerobic microorganism that produces lactate as the major product, and acetate and acetoin as by-products; some strains of this species produce an antimicrobial compound, nisin. Lactate has a strong inhibitory effect on L. lactis growth. On the other hand, hemin has a suppressive effect on lactate production during L. lactis growth under aerobic condition. To achieve the optimum effect of hemin on lactate amount reduction in L. lactis ATCC11454, cultures entailing various conditions were performed with and without hemin. In the culture with hemin, L. lactis growth and lactate reduction improved compared with those in the culture without hemin; that is, lactate production was suppressed by 1.8- and 1.3-fold under batch and fed-batch cultures, respectively. In microaerobic fed-batch culture with hemin, lactate production was sufficiently suppressed. This result suggests that microaerobic fed-batch culture could be applied to the maintenance of the low lactate amount. Under this condition, metabolic shift was observed from lactate to acetoin and acetate. However, no increase in nisin production was observed even though lactate production could significantly decrease in L. lactis ATCC11454.
authors.affiliation: Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Machiko
authors.initials: M
authors.lastname: Nagayasu
authors.forename: Agustin Krisna
authors.initials: AK
authors.lastname: Wardani
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nagahisa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimizu
authors.forename: Suteaki
authors.initials: S
authors.lastname: Shioya
mesh_terms: D000332:Aerobiosis; D003580:Cytochromes / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006427:Hemin / Q000494:pharmacology*; D019344:Lactic Acid / Q000378:metabolism*; D013294:Lactococcus lactis / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D009561:Nisin / Q000096:biosynthesis; D010084:Oxidation-Reduction
chemical_list: D003580:Cytochromes; D009561:Nisin; D019344:Lactic Acid; D006427:Hemin; D005947:Glucose