Fermentation of whey and its permeate using a genetically modified strain of Escherichia coli K12 MG1655 to produce 2,3‐butanediol

Abstract

Whey is generated during cheese manufacturing, and permeate whey is obtained after whey deproteinization. Both effluents contain lactose, which can cause environmental issues if they are released into the environment. The aim of the present study was the valorization of lactose contained in whey and permeate whey via fermentation into 2,3‐butanediol (2,3‐BD) with genetically modified strain of Escherichia coli K12 MG1655. Both effluents were first fermented at various dilution ratios with the culture medium M9 (50:50, 75:25, and 100:0, v/v). The fermentation of undiluted effluents produced the highest 2,3‐BD yield (0.43 g/g lactose) at 72 h. Afterwards, the effects of initial pH, inoculum size and agitation rate on 2,3‐BD yield in flask fermentation of undiluted effluents were studied. The agitation rates of 50 and 200 rpm resulted in lower 2,3‐BD yields compared with 100 rpm (67% lower). The effect of aeration (2.5 vvm) on 2,3‐BD yield was tested in a 2 L bioreactor, where a 2,3‐BD yield of 0.40 g/g lactose was obtained after 24 h. In the present study, it was demonstrated that both whey and permeate whey can be used to produce 2,3‐BD, reaching near 80% of the theoretical yield after 24 h of fermentation.

Midguts of Culex pipiens L. (Diptera: Culicidae) as a potential source of raw milk contamination with pathogens

“…Indeed, there are heat-resistant pathogens within the detected bacteria that may cause serious illness: diarrheal and emetic diseases for people even after heating the milk 39 . All E. coli isolates were subjected to fecal coliform test and our data found that the obtained isolates were able to ferment lactose and form gas when incubated at 44 °C for 24 h. This proved that all obtained E. coli isolates were fecal isolates which transmitted from the pond water through the larvae and passed to adults through the larvae’s developmental stages and retransmitted it to the sterilized milk while feeding through their midguts 40 . According to ISO requirements in dairy product factories receiving milk shipments from live stocks, infected milk with fecal E. coli will subject these shipments to rejection and this loss economically affects milk producers in urban villages 41 .…”

Emerging Trends and Advancements in the Processing of Dairy Whey for Sustainable Biorefining

“…The resulting strain, E. coli JFR12, was studied to produce 2,3-butanediol using whey and whey permeate. The genetically modified strain could be commercialized for high 2,3-BD production (up to 0.41 g/g lactose) under mild operating conditions [177].…”

Metabolic Engineering of Corynebacterium Glutamicum for Efficient Production of Optically Pure (2R,3R)-2,3-Butanediol

“…Constructing microbial cell factories for the production of 2,3butanediol from biomass is considered as a strong alternative. Extensive studies have been carried out to develop e cient microbial cell factories for producing 2,3-butanediol, including Bacillus subtilis [9,10], Bacillus amyloliquefaciens [11,12], Bacillus licheniformis [13,14], Klebsiella oxytoca [15,16], Klebsiella pneumoniae [17,18], Paenibacillus polymyxa [19,20], Serratia marcescens [21,22], Enterobacter cloacae [23,24], Enterobacter aerogenes [25,26], Escherichia coli [3,27], Zymomonas mobilis [28] and Pichia pastoris [29], etc.. Signi cantly, the K. pneumoniae SDM isolated from orchard soil accumulated 150 g/L 2,3-butanediol at 38 h in a 5-L bioreactor, representing the highest titer achieved by the wild type [17]. However, most microorganisms with ability to naturally accumulate 2,3-butanediol produce a mixture of two of the three isomers ((2S,3S)-, (2R,3R)-, meso-2,3-butanediol) [2,30], which limits its application.…”