Biochemical and phylogenetic characterization of the wastewater tolerant Chlamydomonas biconvexa Embrapa|LBA40 strain cultivated in palm oil mill effluent.

The increasing demand for water, food and energy poses challenges for the world´s sustainability. Tropical palm oil is currently the major source of vegetable oil worldwide with a production that exceeds 55 million tons per year, while generating over 200 million tons of palm oil mill effluent (POME). It could potentially be used as a substrate for production of microalgal biomass though. In this study, the microalgal strain Chlamydomonas biconvexa Embrapa|LBA40, originally isolated from a sugarcane vinasse stabilization pond, was selected among 17 strains tested for growth in POME retrieved from anaerobic ponds of a palm oil industrial plant located within the Amazon rainforest region. During cultivation in POME, C. biconvexa Embrapa|LBA40 biomass productivity reached 190.60 mgDW • L-1 • d-1 using 15L airlift flat plate photobioreactors. Carbohydrates comprised the major fraction of algal biomass (31.96%), while the lipidic fraction reached up to 11.3% of dry mass. Reductions of 99% in ammonium and nitrite, as well as 98% reduction in phosphate present in POME were detected after 5 days of algal cultivation. This suggests that the aerobic pond stage, usually used in palm oil industrial plants to reduce POME inorganic load, could be substituted by high rate photobioreactors, significantly reducing the time and area requirements for wastewater treatment. In addition, the complete mitochondrial genome of C. biconvexa Embrapa|LBA40 strain was sequenced, revealing a compact mitogenome, with 15.98 kb in size, a total of 14 genes, of which 9 are protein coding genes. Phylogenetic analysis confirmed the strain taxonomic status within the Chlamydomonas genus, opening up opportunities for future genetic modification and molecular breeding programs in these species.

Danos e sintomatologia de vírus associado à cultura da melancia no estado do Tocantins / Damage and symptoms associated with watermelon virus in Tocantins state

A baixa produtividade e a qualidade dos frutos de melancia estão quase sempre associadas à ocorrência de fitopatogenos, dentre estes destacam as doenças de etiologia viral. Visando o entendimento do complexo vírus/planta de melancia, este trabalho teve o objetivo de avaliar os danos e sintomas induzidos pelos vírus PRSV-W, CMV, ZYMV e WMV, quando inoculados em plantas de melancia, cv. 'Crimson sweet', aos 5, 12 e 19 dias após a emergência (DAE). Os vírus PRSV-W, CMV, ZYMV e WMV influenciaram significativamente (p<0,05) na redução do peso da matéria fresca da parte aérea, na coloração da polpa e redução no peso dos frutos da melancia. Assim como, no teor de sólidos solúveis (ºBrix). Sendo mais significativa em plantas inoculadas com CMV. De modo geral, os vírus PRSV-W, WMV, CMV e ZYMV afetaram o desenvolvimento, a produção da planta da melancia e consequentemente, limita a qualidade do fruto.

Watermelon is one of the most important vegetables grown in Brazil. However, there are several factors responsible for low productivity of crops. Among these stands out the occurrence of associated virus culture. Thus, this study aimed to assess the damage and symptoms of PRSV-W, CMV, ZYMV and WMV inoculated at 5, 12 and 19 days after emergence (DAE). According to the results, PRSV-W viruses, CMV, ZYMV and WMV influenced significantly (p <0.05) reduction in the fresh weight of shoots and on pulp and reduction of fruit weight of inoculated plants. As noted on pulp plants inoculated with PRSV-W, at 5 DAE. With regard to the soluble solids content (° Brix) was dramatically reduced by the virus and inoculation period, in this case being more significant fruits of plants inoculated with CMV presented Brix 3.67 to 5.11 depending on the inoculation period. In general, viruses PRSV-W, WMV, CMV, ZYMV and influence the development and consequently the production of watermelon. Thus, an important factor for the reduction in the quality of fruit produced.