Search Results (4)

A continuous effort is needed to develop sustainable production methods for industrial platform chemicals. B. succiniciproducens, a natural succinic acid-producer, can metabolize five and six carbon atoms containing sugars in pure form as well as from agro-industrial wastes. In our work, we investigate the conversion of industrial by-products, apple pomace from apple juice production, and whey waste from milk processing to succinic acid and other organic acids (lactic, formic, and acetic acid). We obtained a succinic acid yield of 0.224 g/g total consumed fermentable sugars, lactic acid yield was 0.087 g/g, in turn, formic acid was produced at a 0.034 g/g yield, and acetic acid was obtained at 0.010 g/g total consumed fermentable sugars, using a thermal pretreated apple pomace-based medium. In the case of pretreated whey-based medium formulation, we obtained a succinic acid yield of 0.236 g/g consumed lactose, while formic acid and acetic acid were produced as well (0.09 g/g and 0.101 g/g, respectively). We demonstrate that lactose is a promising carbon source for organic acid production by B. succiniciproducens, while our study is the first to propose the use of a similarly available agro-industrial by-product, apple pomace, for the fermentative production of succinic acid by B. succiniciproducens. Full article

Promising green technologies that can overcome the challenges associated with the use of fossil fuels require microorganisms that can effectively ferment lignocellulosic hydrolysate for biochemical production with reduced sensitivity to toxic chemicals derived from the pretreatment process. In this study, a sequential adaptation approach was developed to obtain new bacterial lines from Basfia (B.) succiniciproducens strains, which are adapted to inhibitory compounds of the Arundo (A.) donax hydrolysate or those that accumulate during the fermentation process. The early adaptation stages resulted in newly adapted B. succiniciproducens bacterial lines that can tolerate fermentation end-products such as acetic, lactic, and succinic acids, as well as toxic compounds such as furfural and hydroxymethylfurfural. These adapted bacterial lines were further investigated to assess their ability to produce succinic acid in an MHM medium supplemented with a filtrate of A. donax hydrolysate. Batch growth tests on a small laboratory scale showed that bacterial lines 2E and 4D produced 5.80 ± 0.56 g L⁻¹ and 5.81 ± 0.39 g L⁻¹ of succinic acid, respectively, after 24 h of fermentation. Based also on its growth rate, the adapted bacterial line B. succiniciproducens 4D was selected for tests in a lab-scale fermenter, where it was able to synthesize up to 17.24 ± 0.39 g L⁻¹ of succinate (corresponding to YSA/gluc 0.96 ± 0.02 g g⁻¹ and to YSA/(G + X) 0.48 ± 0.01 g g⁻¹) from MHM medium added with A. donax hydrolysate. Experiments showed an increase of ~17% compared to the control strain. The overall results demonstrate the potential of adapted bacterial lines for succinate production from A. donax hydrolysate and the development of improved technologies for bio-based succinic acid production. Full article

The aim of this study was to investigate the production of succinic acid from lactose concentrate, a by-product of cheese-making, using Actinobacillus succinogenes and Basfia succiniciproducens. Although the ability of these strains to metabolize different sugars is already known, their application in the conversion of lactose bears high potential for optimization. With regard to B. succiniciproducens, this approach is completely novel. In particular, the effect of the medium’s sugar concentration as well as the ability of its supplementation with yeast extract to prevent a lack of essential nutrient proteins and vitamins was examined. Lactose-based media containing sugar concentrations of between 20 and 65 g L⁻¹ and 5 g L⁻¹ of yeast extract were fermented, with both strains showing comparable performances. The best results in terms of succinic acid yield and acid concentration—0.57 g g⁻¹ initial sugar and 23 g L⁻¹—were achieved at an initial sugar concentration of 43 g L⁻¹. The necessity of yeast extract was demonstrated using the sugar-optimized medium without supplementation. As a result, the yield and concentration of succinic acid dropped to 0.34 g g⁻¹ and 13 g L⁻¹ and the sugar consumption decreased from more than 99 to less than 55%. Therefore, the supplementation amount of 5 g L⁻¹ of yeast extract can be regarded as well-balanced. Full article

Succinic acid production through biological fermentation led to new pathways in the integration of renewable feedstock from different industries into biosynthesis. In this article, we investigate the population growth dynamics and succinic acid production potential of the recently isolated natural succinic acid producer, Basfia succiniciproducens, using in silico constraint-based metabolic models as well as in vitro experiments. Our work focuses on the influence of different renewable substrates and added yeast extract on fermentation dynamics, and the produced metabolites of the strain cultured in mineral (minimal) medium. According to our experiments, which were carried out as small-scale fermentations and in bioreactor conditions, glucose is the preferred carbon source, while the addition of 1% yeast extract has a significant positive effect on biomass formation. In the case of B. succiniciproducens cultured in minimal salt medium, a production potential as high as 47.09 mM succinic acid was obtained in these conditions. Industrial applications related to this bacterial strain could contribute to new possibilities for the re-use of byproducts by using fermentation processes, leading to high added-value compounds. Full article