title: Processed milk waste recycling via thermal pretreatment and lactic acid bacteria fermentation.
abstract: Processed milk waste (MW) presents a serious problem within the dairy industries due to its high polluting load. Its chemical oxygen demand (COD) can reach values as high as 80,000 mg O2L-1. This study proposes to reduce the organic load of those wastes using thermal coagulation and recover residual valuable components via fermentation. Thermal process results showed that the COD removal rates exceeded 40% when samples were treated at temperature above 60 °C to reach 72% at 100 °C. Clarified supernatants resulting from thermal treatment of the samples at the temperatures of 60 (MW60), 80 (MW80), and 100 °C (MW100) were fermented using lactic acid bacteria strains without pH control. Lactic strains recorded important final cell yields (5-7 g L-1). Growth mediums prepared using the thermally treated MW produced 73% of the bacterial biomass recorded with a conventional culture medium. At the end of fermentation, mediums were found exhausted from several valuable components. Industrial scale implementation of the proposed process for the recycling of industrial MWs is described and discussed.
authors.affiliation: Laboratoire de Traitement et de Valorisation des Rejets Hydriques (LTVRH), Water Researches and Technologies Center (CERTE), University of Carthage, Tourist route Soliman, BP 273-8020, Nabeul, Tunisia. kasmimariam@gmail.com.
authors.forename: Mariam
authors.identifier: http://orcid.org/0000-0003-3138-0758
authors.initials: M
authors.lastname: Kasmi
authors.affiliation: Laboratoire d'Ecologie et de Technologie Microbienne LETMI, Institut National des Sciences Appliquées et de Technologie (INSAT), Centre Urbain Nord, BP 676 - 1080, Tunis Cedex, Tunisia.
authors.forename: Moktar
authors.initials: M
authors.lastname: Hamdi
authors.affiliation: Laboratoire de Traitement et de Valorisation des Rejets Hydriques (LTVRH), Water Researches and Technologies Center (CERTE), University of Carthage, Tourist route Soliman, BP 273-8020, Nabeul, Tunisia.
authors.forename: Ismail
authors.initials: I
authors.lastname: Trabelsi
mesh_terms: D000818:Animals; D001419:Bacteria; D005285:Fermentation; D019344:Lactic Acid; D008892:Milk; D059027:Recycling
chemical_list: D019344:Lactic Acid
keywords: COD removal; Fermentation; Lactic acid bacteria; Milk waste; Reuse; Thermal coagulation