Citrus peel influences the production of an extracellular naringinase by Staphylococcus xylosus MAK2 in a stirred tank reactor

Staphylococcus xylosus MAK2, Gram-positive coccus, a nonpathogenic member of the coagulase-negative Staphylococcus family was isolated from soil and used to produce naringinase in a stirred tank reactor. An initial medium at pH 5.5 and a cultivation temperature of 30°C was found to be optimal for enzyme production. The addition of Ca⁺² caused stimulation of enzyme activity. The effect of various physico-chemical parameters, such as pH, temperature, agitation, and inducer concentration was studied. The enzyme production was enhanced by the addition of citrus peel powder (CPP) in the optimized medium. A twofold increase in naringinase production was achieved using different technological combinations. The process optimization using technological combinations allowed rapid optimization of large number of variables, which significantly improved enzyme production in a 5-l reactor in 34 h. An increase in sugar concentration (15 gl^-1) in the fermentation medium further increased naringinase production (8.9 IUml^-1) in the bioreactor. Thus, availability of naringinase renders it attractive for potential biotechnological applications in citrus processing industry.

Hydrolysis of citrus peel waste with recombinant rhamnosidase for bioenergy generation

Large amounts of Citrus peel (rich in poly-phenolic compounds) are generated as a by-product of the juice processing industry. Development of alternative, higher valued products utilizing peel waste from grapefruit, oranges, Valencia and other citrus fruit would benefit citrus juice processors by providing them with means to profitably process their peel waste and to avoid environmentally hazardous dumping. Citrus peel waste [CPW, comprised of peel, membranes and juice vesicles] contains a high level of polyphenols and has been used for the production of animal feed, single-cell protein, fibre, enzyme(s), immobilization support & bio-sorbent for heavy metal removal. Naringin (a major tri-hydroxy flavonoid glycoside) is available in large amounts in citrus peel, processed juice and can be extracted from citrus peel waste1. The extracted naringin is further hydrolysed by rhamnosidase to produce D-rhamnose for the production of ethanol and other fermentation products. We have produced a recombinant enzyme2 that has the ability to catalyse the cleavage of terminal rhamnoside groups from naringin to prunin and rhamnose. We have recovered important sugar “D-rhamnose” from the processed waste which would be utilized for ethanol production3. This presentation will summarize current efforts to develop an enzymatic treatment which would facilitate the economical processing of citrus waste for bioenergy generation.

Evaluation of cassava peel waste as lowcost biosorbent for Ni-sorption : equilibrium, kinetics, thermodynamics and mechanism

The feasibility of cassava peel waste for Ni-sorption is evaluated in this work. The biosorbents are characterized by Boehm titration, Fourier transform-infra red (FTIR) spectroscopy, Nitrogen sorption, scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analysis (e.g. elemental mapping) and X-ray photoelectron spectroscopy (XPS). Adsorption experiments are performed in batch mode at 30 °C (303.15 K), 45 °C (318.15 K) and 60 °C (333.15 K). The performance of several temperature dependence forms of isotherm models e.g. Langmuir, Freundlich, Sips and Toth to represent the adsorption equilibrium data is evaluated and contrasted. Sips model demonstrates the best fitting with the maximum uptake capacity for Ni(II) ions of 57 mg/g (0.971 mmol/g) at pH 4.5. For kinetic data correlation, pseudo-second order model shows the best representation. The chemisorption mechanism and thermodynamics aspect are also discussed.

Defending friends : Robert Codrington, George Sarawia and Edward Wogale

Friendship between nineteenth century missionary anthropologists and their converted cultural mentors was central to the gathering of cultural and linguistic information. This chapter traces the friendship between Anglican missionary/anthropologist, Robert Codrington, and brothers George Sarawia - first Melanesian priest - and Edward Wogale - deacon. Codrington's theological perspective on Melanesians and his close friendships with the pupils of the Melanesian Mission School at Norfolk Island allowed him to resist the increasing racialism of Atlantic science in the late nineteenth century and to challenge the evolutionist anthropology of the 1870s and 1880s. The chapter is based, in part, on a cache of letters from Wogale and Sarawia to Codrington written in Mota, the lingua franca of the Anglican Mission.

Constructing girlhood through the periodical press, 1850-1915

Focusing on six popular British girls' periodicals, Kristine Moruzi explores the debate about the shifting nature of Victorian girlhood between 1850 and 1915. During an era of significant political, social, and economic change, girls' periodicals demonstrate the difficulties of fashioning a coherent, consistent model of girlhood. The mixed-genre format of these magazines, Moruzi suggests, allowed inconsistencies and tensions between competing feminine ideals to exist within the same publication. Adopting a case study approach, Moruzi shows that the Monthly Packet, the Girl of the Period Miscellany, the Girl's Own Paper, Atalanta, the Young Woman, and the Girl's Realm each attempted to define and refine a unique type of girl, particularly the religious girl, the 'Girl of the Period,' the healthy girl, the educated girl, the marrying girl, and the modern girl. These periodicals reflected the challenges of embracing the changing conditions of girls' lives while also attempting to maintain traditional feminine ideals of purity and morality. By analyzing the competing discourses within girls' periodicals, Moruzi's book demonstrates how they were able to frame feminine behaviour in ways that both reinforced and redefined the changing role of girls in nineteenth-century society while also allowing girl readers the opportunity to respond to these definitions.