Nisin is a 3.4 kDa antimicrobial peptide, produced by Lactococcus lactis (ATCC 11454). This bacteriocin can inhibit spores gemination and gram-positive bacteria development and has gained visibility in therapeutic use. The bacterial cellulose (CB) has been considered an ideal material and with high quality applied in food and medical-pharmaceutical inputs. Because of all this benefits, it is important to know the system proceeding of CB with nisin. Therefore, it was realize nisin release profile analysis of CBs was performed; analysis of the minimum inhibitory concentration (MIC) of nisin against Escherichia coli ATCC 25922, Pseudomonas aeuroginosa ATCC 9721 and Staphylococus aureus ATCC 10390; antimicrobial stability test, for 100 days at different temperatures of 4º, 25º and 37 ° C against microorganisms: S. aureus e L. sakei. The results show that nisin is released by the CB in 4 hours of contact with medium and the MIC of nisin is 78 µg/mL for S. aureus, doesn’t have gram-negative inhibition. It had stability until 100 days against L. sakei and 60 days for S. aureus. The system proved to be efficient and CB potentiated the antimicrobial action of nisin, acting as a selective barrier for other compounds present in the standard solution, serving as protection of the peptide at different temperatures. The CB loading system can be an ideal antimicrobial stability system for nisin.

Antimicrobial peptides and structurally related peptoids offer potential for the development of new antibiotics. However, progress has been hindered by challenges presented by poor in vivo stability (peptides) or lack of selectivity (peptoids). Herein, we have developed a process to prepare novel hybrid antibacterial agents that combine both linear peptoids (increased in vivo stability compared to peptides) and a nisin fragment (lipid II targeting domain). The hybrid nisin-peptoids prepared were shown to have low µM activity (comparable to natural nisin) against methicillin-resistant Staphylococcus aureus.

Nisin, an antibacterial compound produced by Lactococcus lactis strains, has been approved by the US Food and Drug Administration to be used as a safe food additive to control the growth of undesirable pathogenic bacteria. Nisin is commonly described as a pH-dependent primary metabolite, since its production depends on growth and culture pH evolution. However, the relationship between bacteriocin synthesis and the consumption of the limiting nutrient has not been described until now. Therefore, this study aimed to develop a competitive four-dimensional Lotka Volterra-like equation to describe the relationships between culture pH, limiting nutrient (total nitrogen: TN) consumption and production of biomass (X) and nisin (BT) in four series of batch fermentation with L. lactis CECT 539 in diluted whey (DW)-based media. The developed four-dimensional LV-like equation (with a unique set of parameters) could not be used to describe all cultures belonging to each fermentation series. However, the four-dimensional LV-like equation described accurately each individual culture, providing a good description of the relationships between pH, TN, X and BT, higher values for R2 and F-ratios, lower values (< 10%) for the mean relative percentage deviation modulus, with bias and accuracy factor values approximately equal to one.

Tiger nut (Cyperus esculentus) is an edible perennial grass-like plant that has long been recognized for its health benefits as it is rich in fiber, protein, vitamins, minerals and natural sugars. It can be eaten raw, roasted or made into a refreshing milk which is very nutritive and healthy for consumption. There were several efforts to mass-produce the locally prepared tiger nut milk in our locality, but the fact that it has a shorter shelf-life, brings about a hindrance. The main objective of the present study is to unveil the cause for the easily spoilage of tiger nut milk and device ways to promote its production using different treatments. Tiger nut milk products were prepared using different methods; water soaked tiger nut milk (WSTM), toasted tiger nut milk (TTM), methanol soaked tiger nut milk (MSTM), and the pasteurised tiger nut milk (PTM). Each of these milk proucts prepared was divided into two portions; the first portion is treated with an antibiotic preservative, Nisin and the second portion was left untreated. The two portions were further divided into two; one stored at refrigerating temperature and the other at room temperature, making four different treatments per mixture and a total of 16 samples. These samples were subjected to proximate analysis; protein, fat, moisture, ash and carbohydrate. The chemical composition of the samples was significantly (P < 0.05) affected by processing treatment. All the samples had high moisture content, and a considerable amount of fat. The preservative treated samples that received pasteurized treatment were found to stay more than a week with fair quality. Findings from the study shows that the chemical characteristics of the various milk products were significantly affected by the different processing treatments.