Date Published: January 30, 2019
Publisher: Springer Berlin Heidelberg
Author(s): Jiyun Liu, Peifu Shi, Shahbaz Ahmad, Chunhua Yin, Xiaolu Liu, Yang Liu, Haiyang Zhang, Qianqian Xu, Hai Yan, Qingxiao Li.
Co-culture of Bacillus coagulans and Candida utilis was firstly investigated in the efficient treatment of Lactobacillus fermentation wastewater (LFW) containing total organic carbon (TOC) of 22.0 g/L and total nitrogen (TN) of 2.4 g/L. The utilization of lactic acid by C. utilis was responsible for the relief of feedback inhibition to promote the growth of B. coagulans. The removal ratio of TOC by B. coagulans and C. utilis was only 9.1% and 22.7%, respectively, which was improved to 49.0% by co-culture. The removal ratio of TN by B. coagulans and C. utilis was merely 6.3% and 12.5%, respectively, which was also promoted to 44.6% by co-culture. Both the high growth of B. coagulans and the efficient removal of TOC and TN from LFW was achieved with the co-culture, which is not previously reported and very important in the production of probiotics with the resource utilization of LFW.
Lactic acid bacteria (LAB) are widely distributed in nature and are of great importance and value in agriculture, animal husbandry, food, medicine and manufacturing industries (Leroy and De Vuyst 2014). LAB in the animal body carry out a variety of physiological functions such as regulating normal gastrointestinal tract flora, maintaining micro-ecological balance, and inhibiting the growth of intestinal pathogenic bacteria, which improves the body immunity (Jahn et al. 1996). Mattia Pia Arena provided a fullest possible overview of the antiviral and antifungal activities ascribed to probiotic LAB (Arena et al. 2018). Zeng et al. (2017) and Mao et al. (2017) used LAB as a safe and convenient oral delivery of bioactive peptide and protein drugs for the treatment of diabetes. Furthermore, LAB is commonly used in the manufacture of yoghurt, cheese, sauerkraut (Zhao et al. 2016) and other fermented food (Di Cagno et al. 2016). With the increasing need for LAB, both their culturing scale and the production of Lactobacillus fermentation wastewater (LFW) are rapidly growing. LFW is generally rich with organic compounds such as sugars and protein, as well as lactic acid produced by LAB, which causes pollution and eutrophication in natural water bodies when it is directly released into the environment. Unfortunately, the treatment technology of LFW, especially recycling it as a culture media for other probiotic strains, has not been reported in the literature up to now.
With the increasing need for LAB, both their culturing scale and the production of LFW are rapidly growing, which is generally rich with organic compounds such as sugars and protein, as well as lactic acid produced by LAB (Table 1 and Fig. 4). The release of LFW into natural water body may cause cyanobacterial bloom that can produce toxins such as microcystins and nodularin (Wang et al. 2005), which threatens the safety of drinking water and human health. Because many nutrients such as sugar, protein and organic acids are remained in LFW (Table 1 and Fig. 4), which may waste the resource if it is simply treated by traditional processing. Unfortunately, the treatment technology of LFW, especially recycling it as a culture media for other probiotic strains, has not been reported in the literature up to now. So we firstly investigated the co-culture of two probiotic strains using LFW as a medium.