Integrative growth physiology and transcriptome profiling of probiotic Limosilactobacillus reuteri KUB-AC5

Limosilactobacillus reuteri KUB-AC5 has been widely used as probiotic in chicken for Salmonella reduction. However, a preferable carbon source and growth phase is poorly characterized underlying metabolic responses on growth and inhibition effects of L. reuteri KUB-AC5. This study therefore aimed to investigate transcriptome profiling of L. reuteri KUB-AC5 revealing global metabolic responses when alteration of carbon sources and growth phases. Interestingly, L. reuteri KUB-AC5 grown under sucrose culture showed to be the best for fast growth and inhibition effects against Salmonella Enteritidis S003 growth. Towards the transcriptome profiling and reporter proteins/metabolites analysis, the results showed that amino acid transport via ABC systems as well as sucrose metabolism and transport are key metabolic responses at Logarithmic (L)-phase of L. reuteri KUB-AC5 growth. Considering the Stationary (S)-phase, we found the potential reporter proteins/metabolites involved in carbohydrate metabolism e.g., levansucrase and levan. Promisingly, levansucrase and levan were revealed to be candidates in relation to inhibition effects of L. reuteri KUB-AC5. Throughout this study, L. reuteri KUB-AC5 had a metabolic control in acclimatization to sucrose and energy pools through transcriptional co-regulation, which supported the cell growth and inhibition potentials. This study offers a perspective in optimizing fermentation condition through either genetic or physiological approaches for enhancing probiotic L. reuteri KUB-AC5 properties.

Effect of light exposure on secondary metabolites production of an endophytic fungus Arthrinium rasikravindrae and its antioxidant and anticancer activities

Eltivitasari A, Rahmawati, Gemantari BM, Romadhonsyah F, Nurrochmad A, Wahyuono S, Astuti P. 2021. Effect of light exposure on secondary metabolites production of an endophytic fungus Arthrinium rasikravindrae and its antioxidant and anticancer activities. Biodiversitas 22: 3156-3163. Endophytic microorganisms are one of the promising sources in producing bioactive compounds, to be developed for new drug candidates. They are found to have the ability to generate the same compounds as their host plant. Metabolite producing capacity of the endophytes is known to be affected by light exposure during fermentation process. This study focused on an endophytic fungus Arthrinium rasikravindrae isolated from Coleus amboinicus stem to reveal out its metabolite profiles due to light exposure as well as its bioactivity consequences. A. rasikravindrae was cultured on potato dextrose broth medium for 14 days and fermented in dark and exposed to natural light. Metabolite profiling was performed using TLC and GC-MS analysis. The activities were observed using DPPH assay for antioxidant and MTT assay for cytotoxicity potential. The results showed that A. rasikravindrae ethyl acetate extract produced during dark and exposed to light fermentation conditions contained different compounds but there was some which showed similarity with their host plant. Methyl octadec-9-enoate was found in all fermentation conditions as well as in C. amboinicus stem extract. Besides methyl octadec-9-enoate, methyl palmitate was also found present in both A. rasikravindrae extract fermented exposed to light and its host plant. The antioxidant activity of extract generated from dark fermentation condition was better as compared to that exposed to light with IC50 value of 66.36±0.53 vs 556.92±34.37 µg/mL. However, cytotoxic activity screening against several cancer cell lines exhibited opposing results in which extract from light-exposed fermentation resulted in better cytotoxic activity (IC50 value of 291.40 ± 2.34 µg/mL on WiDr, 336.80 ± 5.05 µg/mL on T47D, and 404.73 ± 3.46 µg/mL on Hela cell lines). Extract obtained from dark fermentation condition showed IC50 value of more than 500 µg/mL in all tested cancer cell lines. Preliminary examination on cytotoxic activity against WiDR cells suggested that the extract from light-exposed fermentation might induce cell death through mechanisms involving cell cycle arrest.

Optimization of solid‐state fermentation condition for crude protein enrichment of rice bran using Rhizopus oryzae in tray bioreactor

Enhancement of crude protein content in rice bran with the solid‐state fermentation method in tray bioreactor using Rhizopus oryzae FNCC 6011 has been investigated. This research aimed to optimize the fermentation condition using the response surface methodology (RSM). The central composite design (CCD) with three independent variables, including substrate thickness (1 to 3 cm), fermentation temperature (28 to 32 °C), and nutrient concentration of KH2PO4 (2 to 6 g/L) used to determine the crude protein enrichment. The quadratic model has successfully described the effect of variable interactions on responses very well as indicated by the F value and p‐value are 11.20 and 0.0041, respectively. The multiple correlation coefficients (R2) of 0.9438 indicated that 94.38% of the model data has approached the actual data with a deviation of 5.62%. The interaction between the variable substrate thickness and the fermentation temperature is the most influential variable on the crude protein enrichment of rice bran, indicated by the highest F value of 24.08 and the lowest p‐value of 0.0027. The highest protein increase of 62.51% was obtained at 2 cm substrate thickness, fermentation temperature of 30 °C, and KH2PO4 concentration of 4 g/L.

Evaluation of Cup Profile for Postharvest in Coffee Variety Castillo from Cauca Department

It is widely accepted that the post-harvest processes of coffee are key factors in determining the final quality of the product. In the department of Cauca in Colombia, this stage is carried out empirically by the farmers of the region, using old methods that do not assure consistent quality. We propose a study to determine the best conditions of temperature and time in post-harvest for the coffee produced in the region. For this purpose, we carried the fermentation and honey process out on different samples of coffee of the Coffea Arabica species of the Castillo variety. Subsequently, the quality of the samples was determined through sensory evaluation by experts. Finally, descriptive statistical techniques applied to the resulting data, and component and hierarchical cluster analysis to find similarities between the samples. The results suggest that the honey process gets better evaluations in the cup profile over any fermentation condition.

Evaluation of Cup Profile for Postharvest in Coffee Variety Castillo from Cauca Department

It is widely accepted that the post-harvest processes of coffee are key factors in determining the final quality of the product. In the department of Cauca in Colombia, this stage is carried out empirically by the farmers of the region, using old methods that do not assure consistent quality. We propose a study to determine the best conditions of temperature and time in post-harvest for the coffee produced in the region. For this purpose, we carried the fermentation and honey process out on different samples of coffee of the Coffea Arabica species of the Castillo variety. Subsequently, the quality of the samples was determined through sensory evaluation by experts. Finally, descriptive statistical techniques applied to the resulting data, and component and hierarchical cluster analysis to find similarities between the samples. The results suggest that the honey process gets better evaluations in the cup profile over any fermentation condition.

Screening of an Alkaline CMCase-Producing Strain and the Optimization of its Fermentation Condition

Objective: Alkaline Carboxymethyl Cellulase (CMCase) is an attractive enzyme for the textile, laundry, pulp, and paper industries; however, commercial preparations with sufficient activity at alkaline conditions are scarce. Methods: High CMCase-producing bacterial isolate, SX9-4, was screened out from soil bacteria, which was identified as Flavobacterium sp. on the basis of 16S rDNA sequencing. Results: The optimum pH and temperature for CMCase reaction were 8.0 and 55°C, respectively. Alkaline CMCase was stable over wide pH (3.0-10.6) and temperature (25-55°C) ranges. Enzyme activity was significantly inhibited by the bivalent cations Mn2+ and Cu2+, and was activated by Fe2+. To improve the alkaline CMCase production of SX9-4, fermentation parameters were selected through onefactor- at-a-time and further carried out by response surface methodologies based on a central composite design. Conclusion: High CMCase production (57.18 U/mL) was achieved under the optimal conditions: 10.53 g/L carboxymethylcellulose sodium, 7.74 g/L glucose, 13.71 g/L peptone, and 5.27 g/L ammonium oxalate.

Quality Improvement of Semi-Wet Terasi by Optimizing the Starter Culture Ratio of Controlled Fermentation

Terasi is a traditional fermented shrimp paste used in Indonesian dish as condiments. Due to its affordability, the paste is widely consumed among the general population, and thus has a great impact in Indonesia. Currently, small-scale or home industry is common for terasi production, and natural fermentation process is the traditional method. Fermentation process is considered complete when desired aromatic odors are obtained. However, this makes the fermentation process subjective, because the decision is solely dependent on the producer. Additionally, natural fermentation poses a higher risk for contamination of microbial pathogens. As a result, the quality of the final product varies greatly from region to region. Therefore, it is necessary to improve the quality of terasi by means of controlled fermentation. Hence, the objective of the research is to optimize the controlled fermentation condition of terasi by determining the most optimal ratio of mixed starter culture. Optimal fermentation conditions were determined by analyzing the effect of the various starter inoculum on the inner microbial community, and results indicated that mixed culture of Staphylococcus saprophyticus, Bacillus subtilis, and Lactobacillus murinus with ratio of 2:1:2 was the most effective for suppressing the growth of unwanted microorganisms. The difference in the microbial composition also resulted to a change in the metabolite profile of terasi.