Conversion of Food Waste into 2,3-Butanediol via Thermophilic Fermentation: Effects of Carbohydrate Content and Nutrient Supplementation

Abstract

Fermentation of food waste into 2,3-butanediol (2,3-BDO), a high-value chemical, is environmentally sustainable and an inexpensive method to recycle waste. Compared to traditional mesophilic fermentation, thermophilic fermentation can inhibit the growth of contaminant bacteria, thereby improving the success of food waste fermentation. However, the effects of sugar and nutrient concentrations in thermophilic food waste fermentations are currently unclear. Here, we investigated the effects of sugar and nutrients (yeast extract (YE) and peptone) concentrations on 2,3-BDO production from fermenting glucose and food waste media using the newly isolated thermophilic Bacillus licheniformis YNP5-TSU. When glucose media was used, fermentation was greatly affected by sugar and nutrient concentrations: excessive glucose (>70 g/L) slowed down the fermentation and low nutrients (2 g/L YE and 1 g/L peptone) caused fermentation failure. However, when food waste media were used with low nutrient addition, the bacteria consumed all 57.8 g/L sugars within 24 h and produced 24.2 g/L 2,3-BDO, equivalent to a fermentation yield of 0.42 g/g. An increase in initial sugar content (72.9 g/L) led to a higher 2,3-BDO titer of 36.7 g/L with a nearly theoretical yield of 0.47 g/g. These findings may provide fundamental knowledge for designing cost-effective food waste fermentation to produce 2,3-BDO.

Food Waste from Campus Dining Hall as a Potential Feedstock for 2,3-Butanediol Production via Non-Sterilized Fermentation

“…Interestingly, though starch is a polymer of glucose, the Pearson coefficient for starch was r = 0.1581, indicating weak to no correlation. We suspect this is due to the fact that the YNP5-TSU Bacillus strain cannot effectively hydrolyze starch [22]. Our results were similar to a previous study by , where high glucose concentrations in food waste led to a high butanol yield.…”

“…To circumvent sterilization, thermophilic fermentation has been shown to be effective and involves higher fermentation temperatures (above 45 • C). One such thermophilic bacteria, Bacillus licheniformis YNP5-TSU [22], was shown in a previous experiment to produce yields of 0.31-0.48 g 2,3-BDO/g sugar from various food wastes (pepper, pineapple and miscellaneous wastes) [21] while also eliminating the sterilization step. However, wastes were from pre-consumer stages during refrigerated preparation of meals.…”

Comprehensive Quality Evaluation for Medicinal and Edible Ziziphi Spinosae Semen before and after Rancidity Based on Traditional Sensory, Physicochemical Characteristics, and Volatile Compounds

“…In this study, bornyl acetate was detected in rancid rather than normal samples, which strongly confirmed that δ -limonene was oxidized and degraded during the rancidity process. In addition, 2,3-butanediol, as high-value chemical, has great potential for diverse industries, including food, cosmetics, agriculture, and pharmaceutical areas [ 43 ]. ( R , R )-2,3-Butanediol and ( R , S )-2,3-butanediol were often detected in foods or TCMs as typical volatile compounds [ 44 , 45 ].…”

Bioprocess development of 2, 3-butanediol production using agro-industrial residues

“…It has been demonstrated that, while conducting a non-sterile fermentation using non-sterile food waste using a thermophilic Bacillus licheniformis YNP5-TSU, the 2,3-BDO production was less in comparison with sterile conditions [ 34 ]. An improvised study using the same bacteria showed a significant increase in 2,3-BDO production because of the increase in initial sugar concentration in the hydrolysate [ 35 ]. It showed the effect of hydrolysis and media components on the diol titers.…”