The commercial reality of bioactive compounds and oil production from microalgal species is constrained by the high cost of production. Downstream processing, which includes harvesting and extraction, can account for 70–80% of the total cost of production. Consequently, from an economic perspective extraction technologies need to be improved. Microalgal cells are difficult to disrupt due to polymers within their cell wall such as algaenan and sporopollenin. Consequently, solvents and disruption devices are required to obtain products of interest from within the cells. Conventional techniques used for cell disruption and extraction are expensive and are often hindered by low efficiencies. Microwave-assisted extraction offers a possibility for extraction of biochemical components including lipids, pigments, carbohydrates, vitamins and proteins, individually and as part of a biorefinery. Microwave technology has advanced since its use in the 1970s. It can cut down working times and result in higher yields and purity of products. In this review, the ability and challenges in using microwave technology are discussed for the extraction of bioactive products individually and as part of a biorefinery approach.

Sources of methane are numerous, and vary greatly in their use and sustainable credentials. A Jekyll and Hyde character, it is a valuable energy source present as geological deposits of natural gas, however it is also potent greenhouse gas, released during many waste management processes. Gas-to-liquid technologies are being investigated as a means to exploit and monetise non-traditional and unutilised methane sources. The product identified as having the greatest potential is methanol due to it being a robust, commercially mature conversion process from methane and its beneficial fuel characteristics. Commercial methane to methanol conversion requires high temperatures and pressures, in an energy intensive and costly process. In contrast methanotrophic bacteria perform the desired transformation under ambient conditions, using methane monooxygenase (MMO) enzymes. Despite the great potential of these bacteria a number of biotechnical difficulties are hindering progress towards an industrially suitable process. We have identified five major challenges that exist as barriers to a viable conversion process that, to our knowledge, have not previously been examined as distinct process challenges. Although biotechnological applications of methanotrophic bacteria have been reviewed in part, no review has comprehensively covered progress and challenges for a methane to methanol process from an industrial perspective. All published examples to date of methanotroph catalysed conversion of methane to methanol are collated, and standardised to allow direct comparison. The focus will be on conversion of methane to methanol by whole-cell, wild type, methanotroph cultures, and the potential for their application in an industrially relevant process. A recent shift in the research community focus from a mainly biological angle to an overall engineering approach, offers potential to exploit methanotrophs in an industrially relevant biotechnological gas-to-liquid process. Current innovations and future opportunities are discussed.

Cyanobacteria are ancient life forms and have adapted to a variety of extreme environments, including high salinity. Biochemical, physiological and genetic studies have contributed to uncovering their underlying survival mechanisms, and as recent studies demonstrate, proteomics has the potential to increase our overall understanding further. To date, most salt-related cyanobacterial proteomic studies have utilised gel electrophoresis with the model organismSynechocystissp. PCC6803. Moreover, focus has been on 2–4% w/v NaCl concentrations within different cellular compartments. Under these conditions,Synechocystissp. PCC6803 was found to respond and adapt to salt stress through synthesis of general and specific stress proteins, altering the protein composition of extracellular layers, and re-directing control of complex central intermediary pathways. Post-transcriptional control was also predicted through non-correlating transcript level data and identification of protein isoforms.In this paper, we also review technical developments with emphasis on improving the quality and quantity of proteomic data and overcoming the detrimental effects of salt on sample preparation and analysis. Developments in gel-free methods include protein and peptide fractionation workflows, which can increase coverage of the proteome (20% inSynechocystissp. PCC6803). Quantitative techniques have also improved in accuracy, resulting in confidence in quantitation approaching or even surpassing that seen in transcriptomic techniques (better than 1.5-fold in differential expression). Furthermore,in vivometabolic labelling andde novoprotein sequencing software have improved the ability to apply proteomics to unsequenced environmental isolates. The example used in this review is a cyanobacterium isolated from a Saharan salt lake.