Adaptive laboratory evolution of nanocellulose-producing bacterium.

Adaptive laboratory evolution through 12 rounds of culturing experiments of the nanocellulose-producing bacterium Komagataeibacter hansenii ATCC 23769 in a liquid fraction from hydrothermal pretreatment of corn stover resulted in a strain that resists inhibition by phenolics. The original strain generated nanocellulose from glucose in standard Hestrin and Schramm (HS) medium, but not from the glucose in pretreatment liquid. K. hansenii cultured in pretreatment liquid treated with activated charcoal to remove inhibitors also converted glucose to bacterial nanocellulose and used xylose as carbon source for growth. The properties of this cellulose were the same as nanocellulose generated from media specifically formulated for bacterial cellulose formation. However, attempts to directly utilize glucose proved unsuccessful due to the toxic character of the lignin-derived phenolics, and in particular, vanillan and ferulic acid. Adaptive laboratory evolution at increasing concentrations of pretreatment liquid from corn stover in HS medium resulted in a strain of K. hansenii that generated bacterial nanocellulose directly from pretreatment liquids of corn stover. The development of this adapted strain positions pretreatment liquid as a valuable resource since K. hansenii is able to convert and thereby concentrate a dilute form of glucose into an insoluble, readily recovered and value-added product-bacterial nanocellulose.

Discovery and development of biological agents to control crop pests / Descoberta e desenvolvimento de agentes de controle biológico de pragas de culturas

Thousands of potential microbial biocontrol agents have been isolated from agricultural fields and crops during research over the last 80 years, yet only a few are in commercial use. Recently, public health and safety concerns about the environmental impact of chemical pesticides have led to consideration of biological control as a natural approach to maintaining crop health. Despite environmental incentives and strong research efforts, commercialization of biocontrol agents has been slow to evolve. The momentum of the chemical industry is difficult to shift, and fermentation processes tend to be more expensive to operate than synthetic chemical processes.Yet there is a demand for biological control products, especially in agricultural niche markets, where there is no chemical competitor. However, given this market demand, the fundamental methods of economical large-scale production and application of biological control agents are lacking. Many aspects of biocontrol agent production and development represent untrodden territory in the progression of industrial fermentation technology beyond its well-established food and pharmaceuticals niche. Distinguishing them from traditional fermentation products, biocontrol agents must not only be produced in high yield but must also meet the following quality criteria: high (near 100 percent) retention of cell viability with maintenance of crop compatibility and consistent bioefficacy during several months of storage. Research examples will be reviewed to illustrate the challenges and strategies of developing processes to manufacture and deliver biological agents for insect, weed, and plant disease control.

Milhares de agentes de controle microbiano potenciais têm sido isolados a partir de campos cultivados ou de culturas pelo esforço da pesquisa nos últimos 80 anos. Entretanto, apenas alguns microrganismos têm uso comercial. Recentemente, medidas de saúde pública e de segurança sobre o impacto ambiental de pesticidas químicos têm levado a se considerar o controle biológico como uma medida promissora para proteção das culturas. Apesar do incentivo ambiental e esforços de pesquisa, a evolução da comercialização dos agentes de biocontrole tem sido lenta. O "momentum" da indústria química é difícil de mudar, e processos fermentativos tendem a ser mais caros e custosos do que os processos químicos sintéticos. Mesmo assim, há demanda para produtos de controle biológico, especialmente em nichos de mercados agrícolas onde não existe um competidor químico. Entretanto, os fundamentos dos métodos econômicos de produção e aplicação dos agentes de biocontrole em larga escala não existem. Muitos aspectos do desenvolvimento e da produção de agentes de controle biológico representam uma área diferenciada na tecnologia de produção industrial por fermentação, já bem estabelecida no nicho farmacêutico e alimentar. Ao se diferenciar dos produtos fermentados tradicionais, os agentes de biocontrole necessitam atingir os critérios de alta (ca. 100 por cento) retenção da viabilidade celular e compatibilidade com a cultura e bioeficiência durante vários meses de armazenagem. Exemplos da pesquisa são discutidos exemplificando-se os desafios e as estratégias dos processo de desenvolvimento para produzir e viabilizar agentes de biocontrole de insetos, ervas-daninhas e doenças.