Cyclodextrin (CD) is an important substance for chemical, pharmaceutical, and food industries. Conventionally, free Escherichia coli (E. coli) cells expressing recombinant cyclodextrin glucanotransferase (CGTase) are used as the biocatalyst for CD production, but the process struggles with low CGTase excretion and CD yield. In this study, E. coli cells were immobilized on hollow‐fiber membranes for β‐CD production, and the process and reaction parameters were optimized via response surface methodology. The reusability of the immobilized cells was also evaluated. The parameter optimization significantly improved β‐CD yield and CGTase excretion, making the process more attractive for industrial applications. The immobilized cells also revealed to be reusable multiple times.

Cell immobilization has been applied in various industries, including chemical manufacturing, food, pharmaceutical, and textile. Recently, innovations in cell immobilization techniques and support materials have been put forward for application in high value-added chemical biosynthesis, such as cyclodextrin (CD). The techniques, support materials, and process parameters of cell immobilization play important roles in achieving high CD yield. This review should help one choose the correct cell immobilization technique and support for a CD biosynthesis setup. Previously, CD biosynthesis utilized free cells, even though they present difficulties such as the low product yield, cell lysis, unstable plasmid, and non-reusable cells. This review highlights how the problems that arise from free-cell bioreactors could be mitigated by cell immobilization. The process conditions of cell immobilization for CD production are also presented.

In this study, to convert high moisture content waste into bio-char, slow pyrolysis of cooked rice waste was proposed. The effects of temperature and duration of slow pyrolysis of cooked rice waste on the fuel properties of the biochar produced were investigated, namely the carbon content and energy density. The cooked rice waste was dried overnight at 80°C prior to pyrolysis to reduce moisture content. The carbon content was measured by using Thermo Finnigan Flash EA 1112 Series Elemental Analyser CHNS-O. Energy density was measured by using IKA Works C—5000 Control bomb calorimeter. Results demonstrated that pyrolysed rice waste at 250°C and 4 hour duration had the highest carbon content (60.30%). Moreover, the calorific values for pyrolysed cooked rice wastes demonstrated that biochar derived from cooked rice waste could be a promising alternative renewable energy source.

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