Potential of Lignocellulosic Waste for Laccase Production by Trametes versicolor under Submerged Fermentation

<b>Background and Objective:</b> Laccase is one of the ligninolytic enzymes classified as a multicopper oxidoreductase group that has the ability in oxidizing phenolic compounds and has widespread use in both food and non-food industries. This enzyme is extracellularly secreted by white-rot fungi, <i>Trametes versicolor</i> (L.) Lloyd in the media containing lignocellulose, for example, kapok banana peels and sawdust. The objective of this study was to evaluate lignocellulosic substrate that able to produce the highest activity of the laccase from the <i>T. versicolor </i>(L.) Lloyd. <b>Materials and Methods:</b> Three substrate variations used in this work included the cultivation media with the addition of either kapok banana peels or sawdust and without using both materials. The inducer (CuSO<sub>4</sub>) was added to each substrate variation and the laccase activity was subsequently measured. <b>Results:</b> The qualitative test result for laccase detection showed that <i>T. versicolor </i>(L.) Lloyd<i> </i>was able to produce this enzyme indicated with a reddish-brown surrounding fungal colony. The fungi cultivated in media with the content of sawdust and 1 mM CuSO<sub>4</sub> yielded the highest laccase activity, reaching 573.6 U L<sup></sup><sup>1</sup> with an OD value of 0.5567<i> </i>and a pH of 5.3 after 7 days of incubation. Meanwhile, the addition of kepok banana peels and 1 mM CuSO<sub>4</sub>, showed the maximum laccase activity (297.7 U L<sup></sup><sup>1</sup>) with the OD value of 0.6932 and a pH of 5 after incubation for 6 days. <b>Conclusion:</b> The white-rot fungi of <i>T. versicolor</i> (L.) Lloyd<i> </i>could produce optimal laccase activity by adding sawdust substrate and 1 mM CuSO<sub>4 </sub>inducer on submerged fermentation.

Indigenous Bacteriocin of Lactic Acid Bacteria from "Dadih" a Fermented Buffalo Milk from West Sumatra, Indonesia as Chicken Meat Preservative

BACKGROUND AND OBJECTIVE

The bacteriocin isolated from fermented buffalo milk from West Sumatra-Indonesia, called Dadih, can be considered as a natural and safe antimicrobial compound for food products. The objective of this research was to evaluate the antimicrobial activity of bacteriocin from Dadih and its effectiveness as a preservative in chicken meat.

MATERIALS AND METHODS

This study used experimental method followed by statistical analysis using 3 experiments with duplication including experiment of meat samples (0 and 10% bacteriocin), storage temperatures (7 and 26°C) and storage duration (0, 1, 2, 3, 4, 5, 6 days and 0, 6, 12 hrs). Each experiment consists of a bacteriocin test, antimicrobial activity assay, physicochemical measurement and storability.

RESULTS

From 10 LAB isolates successfully obtained from Dadih, two isolates with D7 code and D10 code had the highest antimicrobial activity, reaching 11.75 mm and 12 mm, respectively. The meat treated by 10% of bacteriocin gave the lower total microbial (3rd and 5th day) and total E. coli (5th day) at 7 and 26°C. The pH and water activity (aw) values of chicken meat with 10% of bacteriocin showed lower values at 7 and 26°C. The application of bacteriocin to chicken meat was able to inhibit the microbial growth that was still below standard for 3 days at 7°C and 6 hrs at 26°C.

CONCLUSION

Based on research, lactic acid bacteria isolated from buffalo milk curd produced bacteriocin compound which has antimicrobial properties. This bacteriocin showed potential as a natural preservative for chicken meat by inhibiting the growth of pathogen microorganisms.

Chemoprevention of azoxymethane-induced rat aberrant crypt foci by dietary zerumbone isolated from Zingiber zerumbet

The modifying effects of dietary feeding of zerumbone isolated from Zingiber zerumbet on the development of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) were investigated in male F344 rats. Expression of cyclooxygenase (COX)-2 in colonic mucosa exposed to AOM and/or zerumbone was also assayed. In addition, we assessed the effects of zerumbone on cell proliferation activity of crypts by counting silver-stained nucleolar organizer regions protein (AgNORs) in colonic cryptal cell nuclei. To induce ACF rats were given three weekly subcutaneous injections of AOM (15 mg/kg body weight). They were also fed the experimental diet containing 0.01% or 0.05% zerumbone for 5 weeks, starting one week before the first dosing of AOM. AOM exposure produced 84+/-13 ACF/rat at the end of the study (week 5). Dietary administration of zerumbone caused reduction in the frequency of ACF: 72+/-17 (14% reduction) at a dose of 0.01% and 45+/-18 (46% reduction, p<0.001) at a dose of 0.05%. Feeding of zerumbone significantly reduced expression of COX-2 and prostaglandins in colonic mucosa. Zerumbone feeding significantly lowered the number of AgNORs in colonic crypt cell nuclei. These findings might suggest possible chemopreventive ability of zerumbone, through suppression of COX-2 expression, cell proliferating activity of colonic mucosa, and induction of phase II detoxification enzymes in the development of carcinogen-induced ACF.

Screening for in vitro anti-tumor-promoting activities of edible plants from Indonesia

A total of 135 methanol extracts from 48 plant families (107 species) of edible Indonesian plants were screened for their in vitro anti-tumor-promoting activities using the tumor promoter 12-O-hexadecanoylphorbol-13-acetate (HPA)induced Epstein-Barr virus (EBV) activation test in Raji cells. Examined at a concentration of 200 mg/ml, 71% of the extracts inhibited EBV activation by 30% or more. The rate is comparable to the rate observed in our previous tests of edible Thai (60%) plants and much higher than the rate (26%) observed with Japanese plants. In particular, the plant families Zingiberaceae (13/13 active) and Umbelliferae (7/8 active) are suggested to be desirable sources of effective cancer-preventive agents because of the strikingly high frequency of inhibitory activity. Thus, a high potential of edible Southeast Asian plants for cancer chemoprevention is indicated.