Table 2. Dairy wastes valorized products

S/N	Product class	Valorized products	Microbial domains	Microbes/microbial strains	Ref.
1	Biofuel	i. Bio-hydrogen	Archaea	Methanobacterium sp.	Rosa et al. (2014)
		ii. Bio-diesel	Algae	Chlorella protothecoides	Espinosa-Gonzalez et al. (2014)
			Bacteria	Streptococcus thermophilesLactobacillus delbrueckii subsp.Bulgaricus	Vasiljevic and Jelen (2001)
		iii. Biomethane	Yeasts	Kluyveromyces lactisKluyveromyces marxianus	Guimarães et al. (2010)
		iv. Bioethanol		Kluyveromyces marxianusKluyveromyces lactis	Sampaio et al. (2020);Yamahata et al. (2020);You et al. (2017)
			Bacteria	Escherichia coli	Akbas et al. (2014);Sar et al. (2017a);Sar et al. (2017b);Sar et al. (2021)
2	Biopolymer	i. Poly-3-hydroxybutyric acid (PHB)	Bacteria	Pseudomonas hydrogenovora	Koller et al. (2010)
		ii. Polyhydroxyalkanoates (PHAs)		Thermus thermophilusRalstonia eutrophaAlcaligenes latusAeromonas hydrophilaPseudomonas putida	Pantazaki et al. (2009);Sudesh et al. (2000)
		iii. Poly (β-L-malic acid) (PMA)	Filamentous fungi	Aureobasidium pullulans	Xia et al. (2021)
3	Surfactants	i. Biosurfactant	Bacteria	Lactococcus lactisStreptococcus thermophiles	Rodrigues et al. (2006)
4	Bio-active compounds	i. Lactobionic acid		Pseudomonas taetrolens	Goderska et al. (2014)
		ii. Nisin Z		Lactococcus lactis	Amiali et al. (1998)
		iii. Plantaricin		Lactobacillus plantarum	Sharma et al. (2021);Zotta et al. (2020)
		iv. Pediocin		Pediococcus acidilactici	Guerra et al. (2005)
		v. Enterocin AS-48		Enterococcus faecalis	Ananou et al. (2008)
			Yeasts	Kluyveromyces lactis
			Filamentous fungi	Aspergillus oryzae
		vi. Glactooligosaccharides (GOSs)	Bacteria	Bacillus circulansLactobacillus reuteriBifidobacterium bifidumBifidobacterium infantisLactobacillus acidophilusLactobacillus pentosusBifidobacterium longum	Nath et al. (2015)
5	Biomass	i. Single-cell protein (SCP)	Yeasts	Kluyveromyces marxianusKluyveromyces fragilis	Schultz et al. (2006)
		ii. Fungal biomass	Filamentous fungi	Aspergillus oryzae	Mahboubi et al. (2017a);Mahboubi et al. (2017b);Thunuguntla et al. (2018)
6	Enzymes	i. β-galactosidase	Filamentous fungi	Aureobasidium pullulans	Kaur et al. (2015)
			Yeasts	Kluyveromyces marxianusCandida pseudotropicalis	(Kaur et al. (2015)
		ii. α-amylase	Bacteria	Serratia marcescens	Romero et al. (2001)
7	Hormones	i. Gibberellic acid	Filamentous fungi	Fusarium moniliformeAspergillus niger	Cihangir and Aksöza (1997)
8	Vitamins	Vitamin B12	Bacteria	Propionibacterium shermanii	Sar et al. (2022)
9	Solvents	Biobutanol		Clostridium acetobutylicum	Foda et al. (2010)
10	Organic acids	i. Propionic acid		Propionibacterium strains	Atasoy and Cetecioglu (2021);Atasoy et al. (2020)
		ii. Citric acid	Filamentous fungi	Aspergillus niger	El-Holi and Al-Delaimy (2003)
		iii. Lactic acid	Bacteria	Lactobacillus caseiLactococcus lactis	Panesar et al. (2010);Prasad et al. (2014)
		iv. Acetic acid	Yeasts	Kluyveromyces fragilis	Mostafa (2001)
		v. Gluconic acid	Filamentous fungi	Aspergillus niger	Mukhopadhyay et al. (2005)
		vi. Succinic acid	Bacteria	Anaerobiospirillum succiniciproducensActinobacillus succinogenes	Lee et al. (2000);Louasté and Eloutassi (2020)
		vii. Pyruvic acid		Klebsiella oxytoca	Cao et al. (2020)