Enhanced production of optically pure d (–) lactic acid from nutritionally rich Borassus flabellifer sugar and whey protein hydrolysate based–fermentation medium

Abstract

The aim of this study is to optimize the production of optically pure d (-) lactic acid (DLA) employing a cost-effective production medium. Based on the designed biomass approach, Sporolactobacillus inulinus NBRC 13595 was found to exhibit high DLA titer (19.0 g L ) and optical purity (99.6%). A cost-effective medium was constituted using Palmyra palm jaggery (PJ) from Borassus flabellifer and whey protein hydrolysate (WPH) as carbon and nitrogen sources, respectively. Plackett-Burman design indicated that PJ, WPH, and MnSO as significant variables influence DLA production. A rotatable central composite design and response surface methodology were used to optimize the PJ and WPH concentrations. A maximum DLA titer (170.14 g L ) was predicted for 222.24 g L of PJ and 11.99 g L of WPH, respectively. Fermentation experimental results exhibited a maximum DLA titer (189.0 ± 8.53 g L ) and productivity (5.25 ± 0.24 g L H ), which is the highest ever reported for DLA production from a renewable feedstock in the batch process. The present investigation substantiates that the potential application of economically viable raw feedstocks (PJ and WPH) for enhanced DLA production, which is attributed to 2.5-fold reduction in DLA production cost compared with conventional medium.

Recent Advances in D-Lactic Acid Production from Renewable Resources

“…Besides lignocellulosics, other waste or byproduct streams have been suggested as alternative carbon and/or nitrogen sources for d -lactic acid production. Reddy Tadi et al ( 20 ) achieved high d -lactic acid concentrations (189 g/L) by combining sugars derived from Borassus flabellifer with whey protein hydrolysate and employing S. inulinus NBRC 13595. Zhao et al ( 29 ) achieved a final concentration of 145.8 g/L from corn flour hydrolysate using S. inulinus Y2-8.…”

Development of a sweet whey-based medium for culture of Lactobacillus

“…Rich and complex media, like MRS (De Man et al, 1960) or M17 (Terzaghi and Sandine, 1975) (Kurbanoglu, 2004), corn steep liquor (Cornelius et al, 1996;Marcela et al, 2016), whey protein hydrolysates (Mc Comas and Gilliland, 2003;Watanabe et al, 2004), malt sprout extract, casein hydrolysates (Vahvaselkä and Linko, 1987;Chiarini et al, 1992;Horáčková, 2014), baker's yeast cells (Altaf et al, 2007), vegetal substrates (Gardner et al, 2001;Nancib et al, 2001;Charalampopoulos et al, 2002;Djeghri-Hocine et al, 2006;Djeghri-Hocine et al, 2007a), sugarcane juice (Preeti et al, 2016), Palmyra palm jaggery (Reddy Tadi et al, 2017), and de-lipidated egg yolk (DjeghriHocine et al, 2007b). The most efficient nitrogen source seems to be yeast extract (Aeschlimann and Von Stokar, 1990;Arasaratnam et al, 1996;Göksungur and Gűvenç, 1997;Guha et al, 2013;Vethakanraj et al, 2013).…”

Impact of Hydrolysis Methods on the Utilization of Agricultural Residues as Nutrient Source for D-lactic Acid Production by Sporolactobacillus inulinus

“…This versatility and flexibility cannot be achieved with enzymatic hydrolysis methods. Nevertheless, a comparison of chemical hydrolysis and enzymatic hydrolysis with different proteases regarding their hydrolyzing efficiency for the example of rapeseed meal seemed very interesting, because in literature most attempts for substitution of yeast extract were conducted using enzymatically hydrolyzed nutrient sources [7,23]. After enzymatic conversion with different proteases for 48 h, the enzymatically hydrolyzed rapeseed meals were applied as nutrient sources in fermentation leading to a strong variation in productivity of S. inulinus depending on the used protease ( Figure 5).…”

“…Sporolactobacillus inulinus is able to produce enantiomerically pure D-lactic acid and shows high titers and productivities [22,23]. Furthermore, it is characterized by a high substrate and product tolerance [24].…”